diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
new file mode 100644
index 0000000..ff4182a
--- /dev/null
+++ b/.github/workflows/ci.yaml
@@ -0,0 +1,436 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: JohnnyMorganz/stylua-action@v4
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}
+          version: 2.0.2
+          args: --check .
+
+  coverage:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: rhysd/action-setup-vim@v1
+        with:
+          neovim: true
+          version: nightly
+      - name: Clone guard.nvim
+        run: git clone --depth 1 https://github.com/nvimdev/guard.nvim && mv guard.nvim/lua/guard lua/
+      - name: Check test coverage
+        run: |
+          export LUA_PATH="lua/?.lua;lua/?/init.lua;$LUA_PATH"
+          nvim -l scripts/coverage.lua
+
+  test-pip:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: rhysd/action-setup-vim@v1
+        with:
+          neovim: true
+          version: nightly
+      - uses: actions/setup-python@v5
+        with:
+          python-version: '3.12'
+      - uses: leso-kn/gh-actions-lua@master
+        with:
+          luaVersion: "5.1"
+      - uses: hishamhm/gh-actions-luarocks@master
+      - name: Install tools
+        run: |
+          pip install -q autopep8 black cmake-format codespell cpplint djhtml docformatter flake8 isort mdformat mypy pylint ruff sqlfluff yamlfix yapf
+          luarocks install busted --local
+          luarocks install nlua --local
+      - name: Clone guard.nvim
+        run: git clone --depth 1 https://github.com/nvimdev/guard.nvim && mv guard.nvim/lua/guard lua/
+      - name: Run tests
+        run: |
+          export LUA_PATH="lua/?.lua;lua/?/init.lua;$LUA_PATH"
+          busted --lua nlua test/pip/*_spec.lua
+
+  test-npm:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: rhysd/action-setup-vim@v1
+        with:
+          neovim: true
+          version: nightly
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 20
+      - uses: leso-kn/gh-actions-lua@master
+        with:
+          luaVersion: "5.1"
+      - uses: hishamhm/gh-actions-luarocks@master
+      - name: Install tools
+        run: |
+          npm install -g prettier @fsouza/prettierd @biomejs/biome sql-formatter @taplo/cli eslint eslint_d stylelint
+          luarocks install busted --local
+          luarocks install nlua --local
+      - name: Clone guard.nvim
+        run: git clone --depth 1 https://github.com/nvimdev/guard.nvim && mv guard.nvim/lua/guard lua/
+      - name: Run tests
+        run: |
+          export LUA_PATH="lua/?.lua;lua/?/init.lua;$LUA_PATH"
+          busted --lua nlua test/npm/*_spec.lua
+
+  test-go:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: rhysd/action-setup-vim@v1
+        with:
+          neovim: true
+          version: nightly
+      - uses: actions/setup-go@v5
+        with:
+          go-version: stable
+          cache: false
+      - uses: leso-kn/gh-actions-lua@master
+        with:
+          luaVersion: "5.1"
+      - uses: hishamhm/gh-actions-luarocks@master
+      - name: Install tools
+        run: |
+          go install golang.org/x/tools/cmd/goimports@latest
+          go install mvdan.cc/gofumpt@latest
+          go install github.com/segmentio/golines@latest
+          go install github.com/google/yamlfmt/cmd/yamlfmt@latest
+          curl -sSfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh | sh -s -- -b $(go env GOPATH)/bin v1.64.8
+          luarocks install busted --local
+          luarocks install nlua --local
+      - name: Clone guard.nvim
+        run: git clone --depth 1 https://github.com/nvimdev/guard.nvim && mv guard.nvim/lua/guard lua/
+      - name: Run tests
+        run: |
+          export PATH="$HOME/go/bin:$PATH"
+          export LUA_PATH="lua/?.lua;lua/?/init.lua;$LUA_PATH"
+          busted --lua nlua test/go/*_spec.lua
+
+  test-rust:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: rhysd/action-setup-vim@v1
+        with:
+          neovim: true
+          version: nightly
+      - uses: dtolnay/rust-toolchain@stable
+        with:
+          components: rustfmt
+      - uses: dtolnay/rust-toolchain@nightly
+        with:
+          components: rustfmt
+      - uses: leso-kn/gh-actions-lua@master
+        with:
+          luaVersion: "5.1"
+      - uses: hishamhm/gh-actions-luarocks@master
+      - name: Install test tools
+        run: |
+          luarocks install busted --local
+          luarocks install nlua --local
+      - name: Clone guard.nvim
+        run: git clone --depth 1 https://github.com/nvimdev/guard.nvim && mv guard.nvim/lua/guard lua/
+      - name: Run tests
+        run: |
+          export LUA_PATH="lua/?.lua;lua/?/init.lua;$LUA_PATH"
+          busted --lua nlua test/rust/*_spec.lua
+
+  test-lua:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: rhysd/action-setup-vim@v1
+        with:
+          neovim: true
+          version: nightly
+      - uses: leso-kn/gh-actions-lua@master
+        with:
+          luaVersion: "5.1"
+      - uses: hishamhm/gh-actions-luarocks@master
+      - name: Install tools
+        run: |
+          luarocks install busted --local
+          luarocks install nlua --local
+          luarocks install luacheck --local
+          luarocks install fnlfmt --local
+          mkdir -p $HOME/.local/bin
+          wget -q https://github.com/Kampfkarren/selene/releases/download/0.28.0/selene-0.28.0-linux.zip
+          unzip -q selene-0.28.0-linux.zip -d $HOME/.local/bin
+          chmod +x $HOME/.local/bin/selene
+          wget -q https://github.com/JohnnyMorganz/StyLua/releases/download/v2.0.2/stylua-linux-x86_64.zip
+          unzip -q stylua-linux-x86_64.zip -d $HOME/.local/bin
+          chmod +x $HOME/.local/bin/stylua
+      - name: Clone guard.nvim
+        run: git clone --depth 1 https://github.com/nvimdev/guard.nvim && mv guard.nvim/lua/guard lua/
+      - name: Run tests
+        run: |
+          export PATH="$HOME/.local/bin:$PATH"
+          export LUA_PATH="lua/?.lua;lua/?/init.lua;$LUA_PATH"
+          busted --lua nlua test/lua/*_spec.lua
+
+  test-binary:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: rhysd/action-setup-vim@v1
+        with:
+          neovim: true
+          version: nightly
+      - uses: dart-lang/setup-dart@v1
+      - uses: mlugg/setup-zig@v2
+        with:
+          version: 0.15.2
+      - uses: actions/setup-java@v4
+        with:
+          distribution: temurin
+          java-version: 21
+      - uses: leso-kn/gh-actions-lua@master
+        with:
+          luaVersion: "5.1"
+      - uses: hishamhm/gh-actions-luarocks@master
+      - name: Install tools
+        run: |
+          sudo apt-get install -y zsh jq libxml2-utils shellcheck fish pgformatter
+          luarocks install busted --local
+          luarocks install nlua --local
+          mkdir -p $HOME/.local/bin
+          cd $HOME/.local/bin
+          wget -q https://github.com/kamadorueda/alejandra/releases/download/4.0.0/alejandra-x86_64-unknown-linux-musl -O alejandra && chmod +x alejandra
+          wget -q https://github.com/bufbuild/buf/releases/download/v1.47.2/buf-Linux-x86_64 -O buf && chmod +x buf
+          wget -q https://github.com/mrtazz/checkmake/releases/download/0.2.2/checkmake-0.2.2.linux.amd64 -O checkmake && chmod +x checkmake
+          wget -q https://github.com/denoland/deno/releases/download/v2.1.4/deno-x86_64-unknown-linux-gnu.zip && unzip -q deno-x86_64-unknown-linux-gnu.zip && chmod +x deno
+          wget -q https://github.com/hadolint/hadolint/releases/download/v2.12.0/hadolint-Linux-x86_64 -O hadolint && chmod +x hadolint
+          wget -q https://github.com/crate-ci/typos/releases/download/v1.43.3/typos-v1.43.3-x86_64-unknown-linux-musl.tar.gz -O typos.tar.gz && tar xzf typos.tar.gz && chmod +x typos && rm typos.tar.gz
+          wget -q https://github.com/typstyle-rs/typstyle/releases/download/v0.14.4/typstyle-x86_64-unknown-linux-gnu -O typstyle && chmod +x typstyle
+          wget -q https://github.com/cmhughes/latexindent.pl/releases/download/V3.24.4/latexindent-linux -O latexindent && chmod +x latexindent
+          wget -q https://github.com/mvdan/sh/releases/download/v3.10.0/shfmt_v3.10.0_linux_amd64 -O shfmt && chmod +x shfmt
+          wget -q https://github.com/nicklockwood/SwiftFormat/releases/download/0.55.3/swiftformat_linux.zip && unzip -q swiftformat_linux.zip && mv swiftformat_linux swiftformat && chmod +x swiftformat
+          wget -q https://github.com/lukas-reineke/cbfmt/releases/download/v0.2.0/cbfmt_linux-x86_64_v0.2.0.tar.gz -O cbfmt.tar.gz && tar xzf cbfmt.tar.gz -C . cbfmt_linux-x86_64_v0.2.0/cbfmt --strip-components=1 && chmod +x cbfmt && rm cbfmt.tar.gz
+          wget -q https://github.com/pinterest/ktlint/releases/download/1.8.0/ktlint && chmod +x ktlint
+          wget -q https://github.com/google/google-java-format/releases/download/v1.34.1/google-java-format-1.34.1-all-deps.jar && printf '#!/bin/sh\njava -jar %s/google-java-format-1.34.1-all-deps.jar "$@"\n' "$HOME/.local/bin" > google-java-format && chmod +x google-java-format
+          wget -q https://github.com/tombi-toml/tombi/releases/download/v0.7.27/tombi-cli-0.7.27-x86_64-unknown-linux-musl.gz -O tombi.gz && gunzip tombi.gz && chmod +x tombi
+          wget -q https://github.com/detekt/detekt/releases/download/v1.23.7/detekt-cli-1.23.7-all.jar && printf '#!/bin/sh\njava -jar %s/detekt-cli-1.23.7-all.jar "$@"\n' "$HOME/.local/bin" > detekt && chmod +x detekt
+          wget -q https://repo1.maven.org/maven2/com/facebook/ktfmt/0.52/ktfmt-0.52-jar-with-dependencies.jar && printf '#!/bin/sh\njava -jar %s/ktfmt-0.52-jar-with-dependencies.jar "$@"\n' "$HOME/.local/bin" > ktfmt && chmod +x ktfmt
+          wget -q https://github.com/dprint/dprint/releases/download/0.49.0/dprint-x86_64-unknown-linux-gnu.zip && unzip -q dprint-x86_64-unknown-linux-gnu.zip -d . && chmod +x dprint
+          wget -q https://github.com/ndmitchell/hlint/releases/download/v3.10/hlint-3.10-x86_64-linux.tar.gz -O hlint.tar.gz && tar xzf hlint.tar.gz hlint-3.10/hlint --strip-components=1 && chmod +x hlint && rm hlint.tar.gz
+          wget -q https://github.com/tweag/ormolu/releases/download/0.8.0.2/ormolu-x86_64-linux.zip && unzip -q ormolu-x86_64-linux.zip && chmod +x ormolu
+      - name: Clone guard.nvim
+        run: git clone --depth 1 https://github.com/nvimdev/guard.nvim && mv guard.nvim/lua/guard lua/
+      - name: Run tests
+        run: |
+          export PATH="$HOME/.local/bin:$PATH"
+          export LUA_PATH="lua/?.lua;lua/?/init.lua;$LUA_PATH"
+          busted --lua nlua test/binary/*_spec.lua
+
+  test-clang:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: rhysd/action-setup-vim@v1
+        with:
+          neovim: true
+          version: nightly
+      - uses: leso-kn/gh-actions-lua@master
+        with:
+          luaVersion: "5.1"
+      - uses: hishamhm/gh-actions-luarocks@master
+      - name: Install tools
+        run: |
+          sudo apt-get install -y clang-format clang-tidy
+          luarocks install busted --local
+          luarocks install nlua --local
+      - name: Clone guard.nvim
+        run: git clone --depth 1 https://github.com/nvimdev/guard.nvim && mv guard.nvim/lua/guard lua/
+      - name: Run tests
+        run: |
+          export LUA_PATH="lua/?.lua;lua/?/init.lua;$LUA_PATH"
+          for f in test/clang/*_spec.lua; do busted --lua nlua "$f"; done
+
+  test-dotnet:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: rhysd/action-setup-vim@v1
+        with:
+          neovim: true
+          version: nightly
+      - uses: actions/setup-dotnet@v4
+        with:
+          dotnet-version: '8.0'
+      - uses: leso-kn/gh-actions-lua@master
+        with:
+          luaVersion: "5.1"
+      - uses: hishamhm/gh-actions-luarocks@master
+      - name: Install tools
+        run: |
+          dotnet tool install -g csharpier
+          luarocks install busted --local
+          luarocks install nlua --local
+      - name: Clone guard.nvim
+        run: git clone --depth 1 https://github.com/nvimdev/guard.nvim && mv guard.nvim/lua/guard lua/
+      - name: Run tests
+        run: |
+          export LUA_PATH="lua/?.lua;lua/?/init.lua;$LUA_PATH"
+          busted --lua nlua test/dotnet/*_spec.lua
+
+  test-ruby:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: rhysd/action-setup-vim@v1
+        with:
+          neovim: true
+          version: nightly
+      - uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: '3.3'
+      - uses: leso-kn/gh-actions-lua@master
+        with:
+          luaVersion: "5.1"
+      - uses: hishamhm/gh-actions-luarocks@master
+      - name: Install tools
+        run: |
+          gem install rubocop bundler
+          luarocks install busted --local
+          luarocks install nlua --local
+      - name: Setup rubocop Gemfile
+        run: |
+          mkdir -p /tmp/rubocop-test
+          printf "source 'https://rubygems.org'\ngem 'rubocop'\n" > /tmp/rubocop-test/Gemfile
+          cd /tmp/rubocop-test && bundle install
+      - name: Clone guard.nvim
+        run: git clone --depth 1 https://github.com/nvimdev/guard.nvim && mv guard.nvim/lua/guard lua/
+      - name: Run tests
+        run: |
+          export LUA_PATH="lua/?.lua;lua/?/init.lua;$LUA_PATH"
+          busted --lua nlua test/ruby/*_spec.lua
+
+  test-clojure:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: rhysd/action-setup-vim@v1
+        with:
+          neovim: true
+          version: nightly
+      - uses: actions/setup-java@v4
+        with:
+          distribution: temurin
+          java-version: 21
+      - uses: leso-kn/gh-actions-lua@master
+        with:
+          luaVersion: "5.1"
+      - uses: hishamhm/gh-actions-luarocks@master
+      - name: Install Clojure CLI
+        run: |
+          curl -L -O https://github.com/clojure/brew-install/releases/latest/download/linux-install.sh
+          chmod +x linux-install.sh
+          sudo ./linux-install.sh
+      - name: Install tools
+        run: |
+          mkdir -p $HOME/.local/bin
+          printf '#!/bin/sh\nclojure -Sdeps '"'"'{:deps {dev.weavejester/cljfmt {:mvn/version "0.13.0"}}}'"'"' -M -m cljfmt.main "$@"\n' > $HOME/.local/bin/cljfmt && chmod +x $HOME/.local/bin/cljfmt
+          luarocks install busted --local
+          luarocks install nlua --local
+      - name: Pre-warm cljfmt deps
+        run: |
+          export PATH="$HOME/.local/bin:$PATH"
+          echo "" | cljfmt fix - || true
+      - name: Clone guard.nvim
+        run: git clone --depth 1 https://github.com/nvimdev/guard.nvim && mv guard.nvim/lua/guard lua/
+      - name: Run tests
+        run: |
+          export PATH="$HOME/.local/bin:$PATH"
+          export LUA_PATH="lua/?.lua;lua/?/init.lua;$LUA_PATH"
+          busted --lua nlua test/clojure/*_spec.lua
+
+  test-elixir:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: rhysd/action-setup-vim@v1
+        with:
+          neovim: true
+          version: nightly
+      - uses: erlef/setup-beam@v1
+        with:
+          otp-version: '27'
+          elixir-version: '1.17'
+      - uses: leso-kn/gh-actions-lua@master
+        with:
+          luaVersion: "5.1"
+      - uses: hishamhm/gh-actions-luarocks@master
+      - name: Install tools
+        run: |
+          luarocks install busted --local
+          luarocks install nlua --local
+      - name: Clone guard.nvim
+        run: git clone --depth 1 https://github.com/nvimdev/guard.nvim && mv guard.nvim/lua/guard lua/
+      - name: Run tests
+        run: |
+          export LUA_PATH="lua/?.lua;lua/?/init.lua;$LUA_PATH"
+          busted --lua nlua test/elixir/*_spec.lua
+
+  test-nix:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: rhysd/action-setup-vim@v1
+        with:
+          neovim: true
+          version: nightly
+      - uses: cachix/install-nix-action@v27
+      - uses: leso-kn/gh-actions-lua@master
+        with:
+          luaVersion: "5.1"
+      - uses: hishamhm/gh-actions-luarocks@master
+      - name: Install tools
+        run: |
+          nix profile install nixpkgs#nixfmt-rfc-style
+          luarocks install busted --local
+          luarocks install nlua --local
+      - name: Clone guard.nvim
+        run: git clone --depth 1 https://github.com/nvimdev/guard.nvim && mv guard.nvim/lua/guard lua/
+      - name: Run tests
+        run: |
+          export LUA_PATH="lua/?.lua;lua/?/init.lua;$LUA_PATH"
+          busted --lua nlua test/nix/*_spec.lua
+
+  test-swift:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: rhysd/action-setup-vim@v1
+        with:
+          neovim: true
+          version: nightly
+      - uses: swift-actions/setup-swift@v2
+        with:
+          swift-version: '6.0'
+      - uses: leso-kn/gh-actions-lua@master
+        with:
+          luaVersion: "5.1"
+      - uses: hishamhm/gh-actions-luarocks@master
+      - name: Install tools
+        run: |
+          luarocks install busted --local
+          luarocks install nlua --local
+      - name: Clone guard.nvim
+        run: git clone --depth 1 https://github.com/nvimdev/guard.nvim && mv guard.nvim/lua/guard lua/
+      - name: Run tests
+        run: |
+          export LUA_PATH="lua/?.lua;lua/?/init.lua;$LUA_PATH"
+          busted --lua nlua test/swift/*_spec.lua
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
deleted file mode 100644
index ca8ae6c..0000000
--- a/.github/workflows/test.yml
+++ /dev/null
@@ -1,75 +0,0 @@
-name: CI
-
-on: [push, pull_request]
-
-jobs:
-  lint:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v3
-      - name: Stylua
-        uses: JohnnyMorganz/stylua-action@v3
-        with:
-          token: ${{ secrets.GITHUB_TOKEN }}
-          version: latest
-          args: --check .
-
-  test:
-    name: Run Test
-    runs-on: ubuntu-latest
-    permissions:
-      contents: write
-    steps:
-      - uses: actions/checkout@v3
-
-      - name: Test Setup (Neovim Nightly)
-        uses: rhysd/action-setup-vim@v1
-        id: vim
-        with:
-          neovim: true
-          version: nightly
-
-      - name: Test Setup (Lua)
-        uses: leafo/gh-actions-lua@v10
-        with:
-          luaVersion: "luajit-openresty"
-
-      - name: Test Setup (Luarocks)
-        uses: leafo/gh-actions-luarocks@v4
-
-      - name: Package Manager Setup (Python)
-        uses: actions/setup-python@v4
-
-      - name: Package Manager Setup (Rust)
-        uses: actions-rs/toolchain@v1
-        with:
-          toolchain: nightly
-          components: rustfmt, cargo
-
-      - name: Package Manager Setup (npm)
-        uses: actions/setup-node@v3
-        with:
-          node-version: 18
-
-      - name: Package Manager Setup (homebrew)
-        id: set-up-homebrew
-        uses: Homebrew/actions/setup-homebrew@master
-
-      - name: Install Tools
-        shell: bash
-        run: bash ./test/setup.sh
-
-      - name: Formatter Test
-        shell: bash
-        run: |
-          source ./test/env.sh
-          vusted ./test/formatter
-
-      - name: Linter Test
-        shell: bash
-        if: always()
-        run: |
-          source ./test/env.sh
-          for linter_test in ./test/linter/*_spec.lua; do
-              vusted $linter_test
-          done
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..ceb2b98
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+CLAUDE.md
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index cad0f7e..6878a41 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -1,107 +1,75 @@
 # Contributing to guard-collection
 
 - Add your config to `formatter.lua` or `linter/<tool-name>.lua`, if it's a linter don't forget to export it in `linter/init.lua`
-- Write a test. If it's a formatter, show that the config works by giving an example input and verify that the file did got formatted as intended. For example:
+- Write a test in the appropriate `test/<category>/` directory. Tests run tools synchronously via `vim.system():wait()`, bypassing guard.nvim's async pipeline.
+
+Formatter example:
 
 ```lua
 describe('black', function()
   it('can format', function()
-    -- pre-test setup
-    local ft = require('guard.filetype')
-    ft('python'):fmt('black')
-    -- Giving example input to the helper
-    -- the helper creates a new buffer with it, formats, and returns the formatted output
-    local formatted = require('test.formatter.helper').test_with('python', {
-      -- The input code should somewhat reflect the filetype
+    local formatted = require('test.helper').run_fmt('black', 'python', {
       [[def foo(n):]],
       [[    if n in         (1,2,3):]],
       [[        return n+1]],
-      [[a, b = 1,    2]],
-      [[b, a =     a, b]],
-      [[print(  f"The factorial of {a} is: {foo(a)}")]],
     })
-    -- Show that the input is indeed formatted as intended
     assert.are.same({
       [[def foo(n):]],
       [[    if n in (1, 2, 3):]],
       [[        return n + 1]],
-      [[]],
-      [[]],
-      [[a, b = 1, 2]],
-      [[b, a = a, b]],
-      [[print(f"The factorial of {a} is: {foo(a)}")]],
     }, formatted)
   end)
 end)
 ```
 
-- Or if it's a linter, show that the linter's output is converted correctly into neovim diagnostics
+Linter example:
 
 ```lua
-describe('selene', function()
+describe('flake8', function()
   it('can lint', function()
-    -- pre-test setup
-    local helper = require('test.linter.helper')
-    local ns = helper.namespace
-    local ft = require('guard.filetype')
-    ft('lua'):lint('selene')
-    require('guard').setup()
-    -- Giving example input to the helper
-    -- the helper creates a new buffer with it, requires lint, and returns the diagnostics
-    local buf, diagnostics = require('test.linter.helper').test_with('lua', {
-      -- Make sure the input actually has some problems that the linter detects
-      [[local M = {}]],
-      [[function M.foo()]],
-      [[  print("foo")]],
-      [[end]],
-      [[U.bar()]],
-      [[return M]],
+    local helper = require('test.helper')
+    local buf, diagnostics = helper.run_lint('flake8', 'python', {
+      [[import os]],
     })
-    -- Show that the diagnostics is indeed valid
-    assert.are.same({
-      {
-        bufnr = buf,
-        col = 0,
-        end_col = 0,
-        end_lnum = 4,
-        lnum = 4,
-        message = '`U` is not defined [undefined_variable]',
-        -- sometimes the namespace is not fixed
-        namespace = ns,
-        severity = 1,
-        source = 'selene',
-      },
-    }, diagnostics)
+    assert.is_true(#diagnostics > 0)
+    for _, d in ipairs(diagnostics) do
+      assert.equal(buf, d.bufnr)
+      assert.equal('flake8', d.source)
+      assert.is_number(d.lnum)
+      assert.is_string(d.message)
+    end
   end)
 end)
-
 ```
 
-- To run the test you just created, install [vusted](https://github.com/notomo/vusted)
-  ```shell
-  luarocks --lua-version=5.1 install vusted
-  ```
-- Create a symlink so that vusted recognizes guard.nvim namespaces
+For linters with a custom `fn` (cpplint, checkmake, zsh), run the command directly and test `parse()`:
 
-```shell
-ln -s ~/.local/share/nvim/lazy/guard.nvim/lua/guard lua
+```lua
+describe('cpplint', function()
+  it('can lint', function()
+    local linter = require('test.helper').get_linter('cpplint')
+    local tmpfile = '/tmp/guard-test.cpp'
+    vim.fn.writefile({ [[int main(){int x=1;}]] }, tmpfile)
+    local bufnr = vim.api.nvim_create_buf(false, true)
+    local result = vim.system({ 'cpplint', '--filter=-legal/copyright', tmpfile }, {}):wait()
+    local diagnostics = linter.parse(result.stderr or '', bufnr)
+    assert.is_true(#diagnostics > 0)
+  end)
+end)
 ```
 
-- Run the test and make sure it passes
-
+- Add your tool to CI in `.github/workflows/ci.yaml` under the appropriate job
+- Run the test locally:
   ```shell
-
-  vusted ./test/formatter/<tool-name>_spec.lua
-  # or
-  vusted ./test/linter/<tool-name>\_spec.lua
-
-  ok 1 - <tool-name> can format
-  ok 1 - <tool-name> can lint
+  # requires: neovim, lua 5.1, luarocks, busted, nlua
+  # also requires guard.nvim cloned: git clone --depth 1 https://github.com/nvimdev/guard.nvim && mv guard.nvim/lua/guard lua/
+  make test-pip  # or whichever category
   ```
-
-- Modify `test/setup.sh` so that CI installs your tool
-
-- Optionally, format the code with stylua
+- Verify test coverage passes (CI enforces this):
+  ```shell
+  make coverage
+  ```
+- Format with stylua before submitting:
   ```shell
   stylua .
   ```
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..0caedfa
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,51 @@
+LUA_PATH := lua/?.lua;lua/?/init.lua;$(LUA_PATH)
+export LUA_PATH
+
+.PHONY: lint coverage test test-pip test-npm test-go test-rust test-lua test-binary test-clang test-dotnet test-ruby test-clojure test-elixir test-nix test-swift
+
+lint:
+	stylua --check .
+
+coverage:
+	nvim -l scripts/coverage.lua
+
+test: test-pip test-npm test-go test-rust test-lua test-binary test-clang test-dotnet test-ruby test-clojure test-elixir test-nix test-swift
+
+test-pip:
+	busted --lua nlua test/pip/*_spec.lua
+
+test-npm:
+	busted --lua nlua test/npm/*_spec.lua
+
+test-go:
+	busted --lua nlua test/go/*_spec.lua
+
+test-rust:
+	busted --lua nlua test/rust/*_spec.lua
+
+test-lua:
+	busted --lua nlua test/lua/*_spec.lua
+
+test-binary:
+	busted --lua nlua test/binary/*_spec.lua
+
+test-clang:
+	@for f in test/clang/*_spec.lua; do busted --lua nlua "$$f"; done
+
+test-dotnet:
+	busted --lua nlua test/dotnet/*_spec.lua
+
+test-ruby:
+	busted --lua nlua test/ruby/*_spec.lua
+
+test-clojure:
+	busted --lua nlua test/clojure/*_spec.lua
+
+test-elixir:
+	busted --lua nlua test/elixir/*_spec.lua
+
+test-nix:
+	busted --lua nlua test/nix/*_spec.lua
+
+test-swift:
+	busted --lua nlua test/swift/*_spec.lua
diff --git a/lua/guard-collection/formatter.lua b/lua/guard-collection/formatter.lua
index 711dfbb..1c5357b 100644
--- a/lua/guard-collection/formatter.lua
+++ b/lua/guard-collection/formatter.lua
@@ -48,8 +48,8 @@ M.cljfmt = {
 }
 
 M.csharpier = {
-  cmd = 'dotnet-csharpier',
-  args = { '--write-stdout' },
+  cmd = 'csharpier',
+  args = { 'format', '--write-stdout' },
   stdin = true,
 }
 
@@ -299,8 +299,7 @@ M.ruff = {
 
 M.ruff_fix = {
   cmd = 'ruff',
-  args = { '--fix', '-', '--stdin-filename' },
-  stdin = true,
+  args = { 'check', '--fix' },
   fname = true,
 }
 
@@ -319,8 +318,8 @@ M.biome = {
 
 M.buf = {
   cmd = 'buf',
-  args = { 'format' },
-  stdin = true,
+  args = { 'format', '-w' },
+  fname = true,
 }
 
 M.xmllint = {
diff --git a/lua/guard-collection/linter/cpplint.lua b/lua/guard-collection/linter/cpplint.lua
new file mode 100644
index 0000000..4054c95
--- /dev/null
+++ b/lua/guard-collection/linter/cpplint.lua
@@ -0,0 +1,33 @@
+local lint = require('guard.lint')
+
+return {
+  fn = function(_, fname)
+    local co = assert(coroutine.running())
+    vim.system({ 'cpplint', '--filter=-legal/copyright', fname }, {}, function(result)
+      coroutine.resume(co, result.stderr or '')
+    end)
+    return coroutine.yield()
+  end,
+  parse = function(result, bufnr)
+    local diags = {}
+    for line in result:gmatch('[^\n]+') do
+      local lnum, msg, cat, sev = line:match('^[^:]+:(%d+):%s*(.-)%s+%[([^%]]+)%]%s+%[(%d+)%]$')
+      if lnum then
+        local severity = tonumber(sev) >= 3 and vim.diagnostic.severity.ERROR
+          or vim.diagnostic.severity.WARN
+        table.insert(
+          diags,
+          lint.diag_fmt(
+            bufnr,
+            tonumber(lnum) - 1,
+            0,
+            ('[%s] %s'):format(cat, msg),
+            severity,
+            'cpplint'
+          )
+        )
+      end
+    end
+    return diags
+  end,
+}
diff --git a/lua/guard-collection/linter/init.lua b/lua/guard-collection/linter/init.lua
index 51a6599..1a377de 100644
--- a/lua/guard-collection/linter/init.lua
+++ b/lua/guard-collection/linter/init.lua
@@ -3,6 +3,7 @@ return {
   checkmake = require('guard-collection.linter.checkmake'),
   ['clang-tidy'] = require('guard-collection.linter.clang-tidy'),
   codespell = require('guard-collection.linter.codespell'),
+  cpplint = require('guard-collection.linter.cpplint'),
   detekt = require('guard-collection.linter.detekt'),
   eslint = require('guard-collection.linter.eslint'),
   eslint_d = require('guard-collection.linter.eslint_d'),
@@ -23,4 +24,5 @@ return {
   mypy = require('guard-collection.linter.mypy').mypy,
   mypyc = require('guard-collection.linter.mypy').mypyc,
   dmypy = require('guard-collection.linter.mypy').dmypy,
+  zsh = require('guard-collection.linter.zsh'),
 }
diff --git a/lua/guard-collection/linter/ruff.lua b/lua/guard-collection/linter/ruff.lua
index 31bb583..724bca9 100644
--- a/lua/guard-collection/linter/ruff.lua
+++ b/lua/guard-collection/linter/ruff.lua
@@ -3,8 +3,8 @@ local lint = require('guard.lint')
 return {
   cmd = 'ruff',
   args = {
+    'check',
     '-n',
-    '-e',
     '--output-format',
     'json',
     '-',
diff --git a/lua/guard-collection/linter/zsh.lua b/lua/guard-collection/linter/zsh.lua
new file mode 100644
index 0000000..24a2e6b
--- /dev/null
+++ b/lua/guard-collection/linter/zsh.lua
@@ -0,0 +1,24 @@
+local lint = require('guard.lint')
+
+return {
+  fn = function(_, fname)
+    local co = assert(coroutine.running())
+    vim.system({ 'zsh', '-n', fname }, {}, function(result)
+      coroutine.resume(co, result.stderr or '')
+    end)
+    return coroutine.yield()
+  end,
+  parse = function(result, bufnr)
+    local diags = {}
+    for line in result:gmatch('[^\n]+') do
+      local lnum, msg = line:match(':(%d+): (.+)$')
+      if lnum then
+        table.insert(
+          diags,
+          lint.diag_fmt(bufnr, tonumber(lnum) - 1, 0, msg, vim.diagnostic.severity.ERROR, 'zsh')
+        )
+      end
+    end
+    return diags
+  end,
+}
diff --git a/scripts/coverage.lua b/scripts/coverage.lua
new file mode 100644
index 0000000..d12bbf6
--- /dev/null
+++ b/scripts/coverage.lua
@@ -0,0 +1,68 @@
+local skip = {
+  lsp = 'requires a running language server',
+  dmypy = 'mypy daemon mode; requires persistent server',
+  npm_groovy_lint = 'CodeNarc server warm-up hangs CI',
+  npm_groovy_lint_fix = 'CodeNarc server warm-up hangs CI',
+}
+
+local formatters = require('guard-collection.formatter')
+local linters = require('guard-collection.linter')
+
+local all_tools = {}
+for name in pairs(formatters) do
+  if not skip[name] then
+    all_tools[name] = 'formatter'
+  end
+end
+for name in pairs(linters) do
+  if not skip[name] then
+    all_tools[name] = all_tools[name] and 'formatter+linter' or 'linter'
+  end
+end
+
+local test_files = vim.fn.glob('test/**/*_spec.lua', false, true)
+local covered = {}
+for _, file in ipairs(test_files) do
+  local content = table.concat(vim.fn.readfile(file), '\n')
+  for name in pairs(all_tools) do
+    local escaped = vim.pesc(name)
+    local alt = escaped:gsub('_', '[ _]')
+    -- match 'name' in string literals (describe/run_fmt) or .name table access (require().tool)
+    if content:find('[\'"]' .. alt .. '[\'"]') or content:find('%.' .. escaped .. '[^%w_]') then
+      covered[name] = true
+    end
+  end
+end
+
+local missing = {}
+for name in pairs(all_tools) do
+  if not covered[name] then
+    table.insert(missing, name)
+  end
+end
+table.sort(missing)
+
+local total = vim.tbl_count(all_tools)
+local skipped = vim.tbl_count(skip)
+local covered_count = vim.tbl_count(covered)
+local missing_count = #missing
+
+print(
+  string.format(
+    'Tools: %d total, %d skipped, %d covered, %d missing',
+    total,
+    skipped,
+    covered_count,
+    missing_count
+  )
+)
+
+if missing_count > 0 then
+  print('\nMissing tests:')
+  for _, name in ipairs(missing) do
+    print(string.format('  %s (%s)', name, all_tools[name]))
+  end
+  os.exit(1)
+end
+
+print('All testable tools have coverage.')
diff --git a/test/binary/alejandra_spec.lua b/test/binary/alejandra_spec.lua
new file mode 100644
index 0000000..897e41a
--- /dev/null
+++ b/test/binary/alejandra_spec.lua
@@ -0,0 +1,10 @@
+describe('alejandra', function()
+  it('can format', function()
+    local formatted = require('test.helper').run_fmt('alejandra', 'nix', {
+      [[{inputs={nixpkgs.url="github:NixOS/nixpkgs/nixos-unstable";};}]],
+    })
+    assert.are.same({
+      [[{inputs = {nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";};}]],
+    }, formatted)
+  end)
+end)
diff --git a/test/binary/buf_spec.lua b/test/binary/buf_spec.lua
new file mode 100644
index 0000000..32e5786
--- /dev/null
+++ b/test/binary/buf_spec.lua
@@ -0,0 +1,53 @@
+describe('buf', function()
+  local tmpdir = vim.fn.getcwd() .. '/tmp-buf-test'
+
+  setup(function()
+    vim.fn.mkdir(tmpdir, 'p')
+  end)
+
+  teardown(function()
+    vim.fn.delete(tmpdir, 'rf')
+  end)
+
+  it('can format', function()
+    local formatted = require('test.helper').run_fmt('buf', 'proto', {
+      'syntax="proto3";',
+      'package test;',
+      'message Foo{string bar=1;}',
+    }, { tmpdir = tmpdir, cwd = tmpdir })
+    assert.is_true(#formatted > 3)
+  end)
+
+  it('can lint', function()
+    local linter = require('test.helper').get_linter('buf')
+    vim.fn.writefile({ 'version: v2' }, tmpdir .. '/buf.yaml')
+    local protofile = tmpdir .. '/test.proto'
+    vim.fn.writefile({
+      'syntax = "proto3";',
+      'message Foo {',
+      '  string bar = 1;',
+      '}',
+    }, protofile)
+    local bufnr = vim.api.nvim_create_buf(false, true)
+    local result = vim
+      .system({
+        'buf',
+        'lint',
+        '--error-format=json',
+        protofile,
+      }, { cwd = tmpdir })
+      :wait()
+    local output = result.stdout or ''
+    if output == '' then
+      output = result.stderr or ''
+    end
+    local diagnostics = linter.parse(output, bufnr)
+    assert.is_true(#diagnostics > 0)
+    for _, d in ipairs(diagnostics) do
+      assert.equal(bufnr, d.bufnr)
+      assert.equal('buf', d.source)
+      assert.is_number(d.lnum)
+      assert.is_string(d.message)
+    end
+  end)
+end)
diff --git a/test/binary/cbfmt_spec.lua b/test/binary/cbfmt_spec.lua
new file mode 100644
index 0000000..fa49568
--- /dev/null
+++ b/test/binary/cbfmt_spec.lua
@@ -0,0 +1,25 @@
+describe('cbfmt', function()
+  it('can format', function()
+    local tmpdir = '/tmp/cbfmt-test'
+    vim.fn.mkdir(tmpdir, 'p')
+    vim.fn.writefile({ '[languages]' }, tmpdir .. '/.cbfmt.toml')
+    local input = {
+      '# Title',
+      '',
+      'Some text.',
+    }
+    local result = vim
+      .system({ 'cbfmt', '--best-effort', '-p', 'markdown' }, {
+        stdin = table.concat(input, '\n') .. '\n',
+        cwd = tmpdir,
+      })
+      :wait()
+    assert(result.code == 0, 'cbfmt exited ' .. result.code .. ': ' .. (result.stderr or ''))
+    local formatted = vim.split(result.stdout, '\n', { trimempty = true })
+    assert.are.same({
+      '# Title',
+      '',
+      'Some text.',
+    }, formatted)
+  end)
+end)
diff --git a/test/binary/checkmake_spec.lua b/test/binary/checkmake_spec.lua
new file mode 100644
index 0000000..adda48a
--- /dev/null
+++ b/test/binary/checkmake_spec.lua
@@ -0,0 +1,28 @@
+describe('checkmake', function()
+  it('can lint', function()
+    local linter = require('test.helper').get_linter('checkmake')
+    local tmpfile = '/tmp/guard-test.make'
+    local input = {
+      [[all:]],
+      [[\techo hello]],
+    }
+    vim.fn.writefile(input, tmpfile)
+    local bufnr = vim.api.nvim_create_buf(false, true)
+    local result = vim
+      .system({
+        'checkmake',
+        '--format={{.FileName}}:{{.LineNumber}}: [{{.Rule}}] {{.Violation}}\n',
+        tmpfile,
+      }, {})
+      :wait()
+    local output = result.stdout or ''
+    local diagnostics = linter.parse(output, bufnr)
+    assert.is_true(#diagnostics > 0)
+    for _, d in ipairs(diagnostics) do
+      assert.equal(bufnr, d.bufnr)
+      assert.equal('checkmake', d.source)
+      assert.is_number(d.lnum)
+      assert.is_string(d.message)
+    end
+  end)
+end)
diff --git a/test/binary/dart_spec.lua b/test/binary/dart_spec.lua
new file mode 100644
index 0000000..c209797
--- /dev/null
+++ b/test/binary/dart_spec.lua
@@ -0,0 +1,9 @@
+describe('dart', function()
+  it('can format', function()
+    local formatted = require('test.helper').run_fmt('dart', 'dart', {
+      [[void main(){print('hello');}]],
+    })
+    assert.is_true(#formatted > 1)
+    assert.is_true(formatted[1]:find('void main') ~= nil)
+  end)
+end)
diff --git a/test/formatter/deno_fmt_spec.lua b/test/binary/deno_fmt_spec.lua
similarity index 79%
rename from test/formatter/deno_fmt_spec.lua
rename to test/binary/deno_fmt_spec.lua
index 1b359c4..90860ee 100644
--- a/test/formatter/deno_fmt_spec.lua
+++ b/test/binary/deno_fmt_spec.lua
@@ -1,9 +1,6 @@
 describe('deno fmt', function()
   it('can format', function()
-    local ft = require('guard.filetype')
-    ft('typescript'):fmt('deno_fmt')
-
-    local formatted = require('test.formatter.helper').test_with('typescript', {
+    local formatted = require('test.helper').run_fmt('deno_fmt', 'typescript', {
       [[function ]],
       [[    fibonacci(num:]],
       [[    number):]],
diff --git a/test/binary/detekt_spec.lua b/test/binary/detekt_spec.lua
new file mode 100644
index 0000000..9db3049
--- /dev/null
+++ b/test/binary/detekt_spec.lua
@@ -0,0 +1,29 @@
+describe('detekt', function()
+  it('can lint', function()
+    local linter = require('test.helper').get_linter('detekt')
+    local tmpfile = '/tmp/guard-test.kt'
+    local input = {
+      [[fun main() {]],
+      [[    val x = 42]],
+      [[    if (x > 0) {]],
+      [[        println(x)]],
+      [[    }]],
+      [[}]],
+    }
+    vim.fn.writefile(input, tmpfile)
+    local bufnr = vim.api.nvim_create_buf(false, true)
+    local result = vim.system({ 'detekt', '-i', tmpfile }):wait()
+    local output = result.stdout or ''
+    if output == '' then
+      output = result.stderr or ''
+    end
+    local diagnostics = linter.parse(output, bufnr)
+    assert.is_true(#diagnostics > 0)
+    for _, d in ipairs(diagnostics) do
+      assert.equal(bufnr, d.bufnr)
+      assert.equal('detekt', d.source)
+      assert.is_number(d.lnum)
+      assert.is_string(d.message)
+    end
+  end)
+end)
diff --git a/test/binary/dprint_spec.lua b/test/binary/dprint_spec.lua
new file mode 100644
index 0000000..c68342b
--- /dev/null
+++ b/test/binary/dprint_spec.lua
@@ -0,0 +1,26 @@
+describe('dprint', function()
+  it('can format', function()
+    local tmpdir = '/tmp/dprint-test'
+    vim.fn.mkdir(tmpdir, 'p')
+    vim.fn.writefile({
+      '{',
+      '  "typescript": {},',
+      '  "plugins": ["https://plugins.dprint.dev/typescript-0.93.3.wasm"]',
+      '}',
+    }, tmpdir .. '/dprint.json')
+    local input = {
+      [[const x=1;]],
+      [[function foo(  ){return x}]],
+    }
+    local result = vim
+      .system({ 'dprint', 'fmt', '--stdin', 'test.ts' }, {
+        stdin = table.concat(input, '\n') .. '\n',
+        cwd = tmpdir,
+      })
+      :wait()
+    assert(result.code == 0, 'dprint exited ' .. result.code .. ': ' .. (result.stderr or ''))
+    local formatted = vim.split(result.stdout, '\n', { trimempty = true })
+    assert.is_true(#formatted > 0)
+    assert.is_true(formatted[1]:find('const x') ~= nil)
+  end)
+end)
diff --git a/test/binary/fish_indent_spec.lua b/test/binary/fish_indent_spec.lua
new file mode 100644
index 0000000..f2ea7ee
--- /dev/null
+++ b/test/binary/fish_indent_spec.lua
@@ -0,0 +1,14 @@
+describe('fish_indent', function()
+  it('can format', function()
+    local formatted = require('test.helper').run_fmt('fish_indent', 'fish', {
+      [[if test "$x" = "y"]],
+      [[echo hello]],
+      [[end]],
+    })
+    assert.are.same({
+      [[if test "$x" = y]],
+      [[    echo hello]],
+      [[end]],
+    }, formatted)
+  end)
+end)
diff --git a/test/binary/google-java-format_spec.lua b/test/binary/google-java-format_spec.lua
new file mode 100644
index 0000000..38fb99f
--- /dev/null
+++ b/test/binary/google-java-format_spec.lua
@@ -0,0 +1,9 @@
+describe('google-java-format', function()
+  it('can format', function()
+    local formatted = require('test.helper').run_fmt('google-java-format', 'java', {
+      'class A{void m(){int x=1;}}',
+    })
+    assert.is_true(#formatted > 1)
+    assert.is_true(formatted[1]:find('class A') ~= nil)
+  end)
+end)
diff --git a/test/binary/hadolint_spec.lua b/test/binary/hadolint_spec.lua
new file mode 100644
index 0000000..0ba3f02
--- /dev/null
+++ b/test/binary/hadolint_spec.lua
@@ -0,0 +1,29 @@
+describe('hadolint', function()
+  it('can lint', function()
+    local linter = require('test.helper').get_linter('hadolint')
+    local tmpfile = '/tmp/guard-test.dockerfile'
+    local input = {
+      [[FROM ubuntu]],
+      [[RUN apt-get install python]],
+    }
+    vim.fn.writefile(input, tmpfile)
+    local bufnr = vim.api.nvim_create_buf(false, true)
+    local result = vim
+      .system({
+        'hadolint',
+        '--no-fail',
+        '--format=json',
+        tmpfile,
+      })
+      :wait()
+    local output = result.stdout or ''
+    local diagnostics = linter.parse(output, bufnr)
+    assert.is_true(#diagnostics > 0)
+    for _, d in ipairs(diagnostics) do
+      assert.equal(bufnr, d.bufnr)
+      assert.equal('hadolint', d.source)
+      assert.is_number(d.lnum)
+      assert.is_string(d.message)
+    end
+  end)
+end)
diff --git a/test/binary/hlint_spec.lua b/test/binary/hlint_spec.lua
new file mode 100644
index 0000000..9584413
--- /dev/null
+++ b/test/binary/hlint_spec.lua
@@ -0,0 +1,17 @@
+describe('hlint', function()
+  it('can lint', function()
+    local helper = require('test.helper')
+    local buf, diagnostics = helper.run_lint('hlint', 'haskell', {
+      [[concat $ map escapeC s]],
+      [[ftable ++ (map (\ (c, x) -> (toUpper c, urlEncode x)) ftable)]],
+      [[mapM (delete_line (fn2fp f) line) old]],
+    })
+    assert.is_true(#diagnostics > 0)
+    for _, d in ipairs(diagnostics) do
+      assert.equal(buf, d.bufnr)
+      assert.equal('hlint', d.source)
+      assert.is_number(d.lnum)
+      assert.is_string(d.message)
+    end
+  end)
+end)
diff --git a/test/binary/jq_spec.lua b/test/binary/jq_spec.lua
new file mode 100644
index 0000000..9612a1b
--- /dev/null
+++ b/test/binary/jq_spec.lua
@@ -0,0 +1,13 @@
+describe('jq', function()
+  it('can format', function()
+    local formatted = require('test.helper').run_fmt('jq', 'json', {
+      [[{"b":2,"a":1}]],
+    })
+    assert.are.same({
+      [[{]],
+      [[  "b": 2,]],
+      [[  "a": 1]],
+      [[}]],
+    }, formatted)
+  end)
+end)
diff --git a/test/binary/ktfmt_spec.lua b/test/binary/ktfmt_spec.lua
new file mode 100644
index 0000000..f249720
--- /dev/null
+++ b/test/binary/ktfmt_spec.lua
@@ -0,0 +1,9 @@
+describe('ktfmt', function()
+  it('can format', function()
+    local formatted = require('test.helper').run_fmt('ktfmt', 'kt', {
+      [[fun main(){val x=1;println(x)}]],
+    })
+    assert.is_true(#formatted > 1)
+    assert.is_true(formatted[1]:find('fun main') ~= nil)
+  end)
+end)
diff --git a/test/binary/ktlint_spec.lua b/test/binary/ktlint_spec.lua
new file mode 100644
index 0000000..9e99a55
--- /dev/null
+++ b/test/binary/ktlint_spec.lua
@@ -0,0 +1,42 @@
+describe('ktlint', function()
+  it('can format', function()
+    local formatted = require('test.helper').run_fmt('ktlint', 'kt', {
+      [[fun main() {]],
+      [[    val x=1]],
+      [[    println(x)]],
+      [[}]],
+    })
+    assert.are.same({
+      [[fun main() {]],
+      [[    val x = 1]],
+      [[    println(x)]],
+      [[}]],
+    }, formatted)
+  end)
+
+  it('can lint', function()
+    local linter = require('test.helper').get_linter('ktlint')
+    local tmpfile = '/tmp/guard-test.kt'
+    local input = {
+      [[fun main() {]],
+      [[    val x=1]],
+      [[    println(x)]],
+      [[}]],
+    }
+    vim.fn.writefile(input, tmpfile)
+    local bufnr = vim.api.nvim_create_buf(false, true)
+    local result = vim.system({ 'ktlint', '--log-level=error', tmpfile }):wait()
+    local output = result.stdout or ''
+    if output == '' then
+      output = result.stderr or ''
+    end
+    local diagnostics = linter.parse(output, bufnr)
+    assert.is_true(#diagnostics > 0)
+    for _, d in ipairs(diagnostics) do
+      assert.equal(bufnr, d.bufnr)
+      assert.equal('ktlint', d.source)
+      assert.is_number(d.lnum)
+      assert.is_string(d.message)
+    end
+  end)
+end)
diff --git a/test/formatter/latexindent_spec.lua b/test/binary/latexindent_spec.lua
similarity index 80%
rename from test/formatter/latexindent_spec.lua
rename to test/binary/latexindent_spec.lua
index c4bba5d..4f22713 100644
--- a/test/formatter/latexindent_spec.lua
+++ b/test/binary/latexindent_spec.lua
@@ -1,9 +1,6 @@
 describe('latexindent', function()
   it('can format', function()
-    local ft = require('guard.filetype')
-    ft('latex'):fmt('latexindent')
-
-    local formatted = require('test.formatter.helper').test_with('latex', {
+    local formatted = require('test.helper').run_fmt('latexindent', 'latex', {
       [[\documentclass{article}]],
       [[\begin{document}]],
       [[Shopping list]],
diff --git a/test/binary/ormolu_spec.lua b/test/binary/ormolu_spec.lua
new file mode 100644
index 0000000..52edf0a
--- /dev/null
+++ b/test/binary/ormolu_spec.lua
@@ -0,0 +1,13 @@
+describe('ormolu', function()
+  it('can format', function()
+    local formatted = require('test.helper').run_fmt('ormolu', 'hs', {
+      [[module Main where]],
+      [[main = putStrLn "hello"]],
+    })
+    assert.are.same({
+      [[module Main where]],
+      [[]],
+      [[main = putStrLn "hello"]],
+    }, formatted)
+  end)
+end)
diff --git a/test/binary/pg_format_spec.lua b/test/binary/pg_format_spec.lua
new file mode 100644
index 0000000..3e44720
--- /dev/null
+++ b/test/binary/pg_format_spec.lua
@@ -0,0 +1,9 @@
+describe('pg_format', function()
+  it('can format', function()
+    local formatted = require('test.helper').run_fmt('pg_format', 'sql', {
+      [[select id, name from users where id = 1;]],
+    })
+    assert.is_true(#formatted > 1)
+    assert.is_truthy(formatted[1]:match('SELECT'))
+  end)
+end)
diff --git a/test/binary/shellcheck_spec.lua b/test/binary/shellcheck_spec.lua
new file mode 100644
index 0000000..5381bd9
--- /dev/null
+++ b/test/binary/shellcheck_spec.lua
@@ -0,0 +1,30 @@
+describe('shellcheck', function()
+  it('can lint', function()
+    local linter = require('test.helper').get_linter('shellcheck')
+    local tmpfile = '/tmp/guard-test.sh'
+    local input = {
+      [[#!/bin/sh]],
+      [[echo $FOO]],
+    }
+    vim.fn.writefile(input, tmpfile)
+    local bufnr = vim.api.nvim_create_buf(false, true)
+    local result = vim
+      .system({
+        'shellcheck',
+        '--format',
+        'json1',
+        '--external-sources',
+        tmpfile,
+      })
+      :wait()
+    local output = result.stdout or ''
+    local diagnostics = linter.parse(output, bufnr)
+    assert.is_true(#diagnostics > 0)
+    for _, d in ipairs(diagnostics) do
+      assert.equal(bufnr, d.bufnr)
+      assert.equal('shellcheck', d.source)
+      assert.is_number(d.lnum)
+      assert.is_string(d.message)
+    end
+  end)
+end)
diff --git a/test/binary/shfmt_spec.lua b/test/binary/shfmt_spec.lua
new file mode 100644
index 0000000..e6c3a20
--- /dev/null
+++ b/test/binary/shfmt_spec.lua
@@ -0,0 +1,16 @@
+describe('shfmt', function()
+  it('can format', function()
+    local formatted = require('test.helper').run_fmt('shfmt', 'sh', {
+      [[#!/bin/sh]],
+      [[if [ "$x" = "y" ]; then]],
+      [[echo "hello"]],
+      [[fi]],
+    })
+    assert.are.same({
+      [[#!/bin/sh]],
+      [[if [ "$x" = "y" ]; then]],
+      '\techo "hello"',
+      [[fi]],
+    }, formatted)
+  end)
+end)
diff --git a/test/formatter/swiftformat.lua b/test/binary/swiftformat_spec.lua
similarity index 64%
rename from test/formatter/swiftformat.lua
rename to test/binary/swiftformat_spec.lua
index 2580c0e..1c6b640 100644
--- a/test/formatter/swiftformat.lua
+++ b/test/binary/swiftformat_spec.lua
@@ -1,9 +1,6 @@
 describe('swiftformat', function()
   it('can format', function()
-    local ft = require('guard.filetype')
-    ft('swift'):fmt('swiftformat')
-
-    local formatted = require('test.formatter.helper').test_with('swift', {
+    local formatted = require('test.helper').run_fmt('swiftformat', 'swift', {
       [[func myFunc()        { ]],
       [[print("hello")  ]],
       [[  }]],
diff --git a/test/binary/tombi_spec.lua b/test/binary/tombi_spec.lua
new file mode 100644
index 0000000..8808fef
--- /dev/null
+++ b/test/binary/tombi_spec.lua
@@ -0,0 +1,16 @@
+describe('tombi', function()
+  it('can format', function()
+    local formatted = require('test.helper').run_fmt('tombi', 'toml', {
+      '[package]',
+      'name="test"',
+      'version  =   "0.1.0"',
+    })
+    assert.is_true(#formatted > 0)
+    for _, line in ipairs(formatted) do
+      if line:find('name') then
+        assert.is_true(line:find('name = ') ~= nil)
+        break
+      end
+    end
+  end)
+end)
diff --git a/test/binary/typos_spec.lua b/test/binary/typos_spec.lua
new file mode 100644
index 0000000..a942017
--- /dev/null
+++ b/test/binary/typos_spec.lua
@@ -0,0 +1,14 @@
+describe('typos', function()
+  it('can lint', function()
+    local helper = require('test.helper')
+    local buf, diagnostics = helper.run_lint('typos', 'txt', {
+      [[teh quick brown fox]],
+    })
+    assert.is_true(#diagnostics > 0)
+    for _, d in ipairs(diagnostics) do
+      assert.equal(buf, d.bufnr)
+      assert.is_number(d.lnum)
+      assert.is_string(d.message)
+    end
+  end)
+end)
diff --git a/test/binary/typstyle_spec.lua b/test/binary/typstyle_spec.lua
new file mode 100644
index 0000000..7169c4f
--- /dev/null
+++ b/test/binary/typstyle_spec.lua
@@ -0,0 +1,10 @@
+describe('typstyle', function()
+  it('can format', function()
+    local formatted = require('test.helper').run_fmt('typstyle', 'typ', {
+      [[#let x =    1]],
+    })
+    assert.are.same({
+      [[#let x = 1]],
+    }, formatted)
+  end)
+end)
diff --git a/test/binary/xmllint_spec.lua b/test/binary/xmllint_spec.lua
new file mode 100644
index 0000000..5c1f3fd
--- /dev/null
+++ b/test/binary/xmllint_spec.lua
@@ -0,0 +1,13 @@
+describe('xmllint', function()
+  it('can format', function()
+    local formatted = require('test.helper').run_fmt('xmllint', 'xml', {
+      [[<root><child attr="val">text</child></root>]],
+    })
+    assert.are.same({
+      [[<?xml version="1.0"?>]],
+      [[<root>]],
+      [[  <child attr="val">text</child>]],
+      [[</root>]],
+    }, formatted)
+  end)
+end)
diff --git a/test/binary/zigfmt_spec.lua b/test/binary/zigfmt_spec.lua
new file mode 100644
index 0000000..d978f96
--- /dev/null
+++ b/test/binary/zigfmt_spec.lua
@@ -0,0 +1,10 @@
+describe('zigfmt', function()
+  it('can format', function()
+    local formatted = require('test.helper').run_fmt('zigfmt', 'zig', {
+      [[const    std   =   @import(   "std"   );]],
+    })
+    assert.are.same({
+      [[const std = @import("std");]],
+    }, formatted)
+  end)
+end)
diff --git a/test/binary/zsh_spec.lua b/test/binary/zsh_spec.lua
new file mode 100644
index 0000000..78332d2
--- /dev/null
+++ b/test/binary/zsh_spec.lua
@@ -0,0 +1,18 @@
+describe('zsh', function()
+  it('can lint', function()
+    local linter = require('test.helper').get_linter('zsh')
+    local tmpfile = '/tmp/guard-test.zsh'
+    vim.fn.writefile({ 'if true; then' }, tmpfile)
+    local bufnr = vim.api.nvim_create_buf(false, true)
+    local result = vim.system({ 'zsh', '-n', tmpfile }, {}):wait()
+    local output = result.stderr or ''
+    local diagnostics = linter.parse(output, bufnr)
+    assert.is_true(#diagnostics > 0)
+    for _, d in ipairs(diagnostics) do
+      assert.equal(bufnr, d.bufnr)
+      assert.equal('zsh', d.source)
+      assert.is_number(d.lnum)
+      assert.is_string(d.message)
+    end
+  end)
+end)
diff --git a/test/formatter/clang-format_spec.lua b/test/clang/clang-format_spec.lua
similarity index 81%
rename from test/formatter/clang-format_spec.lua
rename to test/clang/clang-format_spec.lua
index 2ca886c..c5bb344 100644
--- a/test/formatter/clang-format_spec.lua
+++ b/test/clang/clang-format_spec.lua
@@ -1,9 +1,6 @@
 describe('clang-format', function()
   it('can format', function()
-    local ft = require('guard.filetype')
-    ft('c'):fmt('clang-format')
-
-    local formatted = require('test.formatter.helper').test_with('c', {
+    local formatted = require('test.helper').run_fmt('clang-format', 'c', {
       [[#include <stdio.h>]],
       [[int main() {]],
       [[                int x = 0x87654321]],
diff --git a/test/clang/clang-tidy_spec.lua b/test/clang/clang-tidy_spec.lua
new file mode 100644
index 0000000..d3ef122
--- /dev/null
+++ b/test/clang/clang-tidy_spec.lua
@@ -0,0 +1,21 @@
+describe('clang-tidy', function()
+  it('can lint', function()
+    local helper = require('test.helper')
+    local buf, diagnostics = helper.run_lint('clang-tidy', 'c', {
+      [[#include <stdio.h>]],
+      [[int main() {]],
+      [[    int x = 10;]],
+      [[    int y = 0;]],
+      [[    printf("%d", x / y);]],
+      [[    return 0;]],
+      [[}]],
+    })
+    assert.is_true(#diagnostics > 0)
+    for _, d in ipairs(diagnostics) do
+      assert.equal(buf, d.bufnr)
+      assert.equal('clang-tidy', d.source)
+      assert.is_number(d.lnum)
+      assert.is_string(d.message)
+    end
+  end)
+end)
diff --git a/test/clojure/cljfmt_spec.lua b/test/clojure/cljfmt_spec.lua
new file mode 100644
index 0000000..f333606
--- /dev/null
+++ b/test/clojure/cljfmt_spec.lua
@@ -0,0 +1,11 @@
+describe('cljfmt', function()
+  it('can format', function()
+    local formatted = require('test.helper').run_fmt('cljfmt', 'clj', {
+      [[(defn hello]],
+      [[  [name]  (println "hello"]],
+      [[name))]],
+    })
+    assert.is_true(#formatted > 0)
+    assert.is_true(formatted[1]:find('defn hello') ~= nil)
+  end)
+end)
diff --git a/test/dotnet/csharpier_spec.lua b/test/dotnet/csharpier_spec.lua
new file mode 100644
index 0000000..2429d22
--- /dev/null
+++ b/test/dotnet/csharpier_spec.lua
@@ -0,0 +1,9 @@
+describe('csharpier', function()
+  it('can format', function()
+    local formatted = require('test.helper').run_fmt('csharpier', 'cs', {
+      [[class A{void M(){int x=1;}}]],
+    })
+    assert.is_true(#formatted > 1)
+    assert.is_true(formatted[1]:find('class A') ~= nil)
+  end)
+end)
diff --git a/test/elixir/mixformat_spec.lua b/test/elixir/mixformat_spec.lua
new file mode 100644
index 0000000..c11c294
--- /dev/null
+++ b/test/elixir/mixformat_spec.lua
@@ -0,0 +1,9 @@
+describe('mixformat', function()
+  it('can format', function()
+    local formatted = require('test.helper').run_fmt('mixformat', 'ex', {
+      [[defmodule Foo do  def bar(  x,y) do  x+y end end]],
+    })
+    assert.is_true(#formatted > 0)
+    assert.is_true(formatted[1]:find('defmodule Foo') ~= nil)
+  end)
+end)
diff --git a/test/env.sh b/test/env.sh
deleted file mode 100644
index a9788c8..0000000
--- a/test/env.sh
+++ /dev/null
@@ -1,4 +0,0 @@
-#! /bin/bash
-export PATH="/home/linuxbrew/.linuxbrew/opt/clang-format/bin:$PATH"
-export PATH="$HOME/.local/bin:$PATH"
-export PATH="/home/linuxbrew/.linuxbrew/bin:$PATH"
diff --git a/test/formatter/alejandra_spec.lua b/test/formatter/alejandra_spec.lua
deleted file mode 100644
index 5282dbb..0000000
--- a/test/formatter/alejandra_spec.lua
+++ /dev/null
@@ -1,17 +0,0 @@
-describe('alejandra', function()
-  it('can format', function()
-    -- pre-test setup
-    local ft = require('guard.filetype')
-    ft('nix'):fmt('alejandra')
-    -- Giving example input to the helper
-    -- the helper creates a new buffer with it, formats, and returns the formatted output
-    local formatted = require('test.formatter.helper').test_with('nix', {
-      -- The input code should somewhat reflect the filetype
-      [[{inputs={nixpkgs.url="github:NixOS/nixpkgs/nixos-unstable";};}]],
-    })
-    -- Show that the input is indeed formatted as intended
-    assert.are.same({
-      [[{inputs = {nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";};}]],
-    }, formatted)
-  end)
-end)
diff --git a/test/formatter/buf_spec.lua b/test/formatter/buf_spec.lua
deleted file mode 100644
index 1ea646a..0000000
--- a/test/formatter/buf_spec.lua
+++ /dev/null
@@ -1,17 +0,0 @@
-describe('buf', function()
-  it('can format', function()
-    local ft = require('guard.filetype')
-    ft('proto'):fmt('buf')
-
-    local formatted = require('test.formatter.helper').test_with('proto', {
-      [[syntax = "proto3"; message Foo { string bar = 1; }]],
-    })
-    assert.are.same({
-      [[syntax = "proto3";]],
-      [[]],
-      [[message Foo {]],
-      [[  string bar = 1;]],
-      [[}]],
-    }, formatted)
-  end)
-end)
diff --git a/test/formatter/helper.lua b/test/formatter/helper.lua
deleted file mode 100644
index 28292fd..0000000
--- a/test/formatter/helper.lua
+++ /dev/null
@@ -1,18 +0,0 @@
-local M = {}
-local api = vim.api
-
-function M.test_with(ft, input)
-  local cmd = require('guard.filetype')(ft).formatter[1].cmd
-  assert(not cmd or vim.fn.executable(cmd) == 1)
-  local bufnr = api.nvim_create_buf(true, false)
-  vim.bo[bufnr].filetype = ft
-  api.nvim_set_current_buf(bufnr)
-  api.nvim_buf_set_lines(bufnr, 0, -1, false, input)
-  -- To provide fname
-  vim.cmd('silent! write! /tmp/file.' .. ft)
-  require('guard.format').do_fmt(bufnr)
-  vim.wait(3000)
-  return api.nvim_buf_get_lines(bufnr, 0, -1, false)
-end
-
-return M
diff --git a/test/formatter/sqlfluff_spec.lua b/test/formatter/sqlfluff_spec.lua
deleted file mode 100644
index 393713c..0000000
--- a/test/formatter/sqlfluff_spec.lua
+++ /dev/null
@@ -1,42 +0,0 @@
-describe('sqlfluff', function()
-  it('can format', function()
-    local ft = require('guard.filetype')
-    local tool = ft('sql'):fmt('sqlfluff')
-    tool.formatter[1].args = vim.list_extend(tool.formatter[1].args, { '--dialect', 'ansi' })
-
-    local formatted = require('test.formatter.helper').test_with('sql', {
-      [[SELECT          *]],
-      [[FROM]],
-      [[         World         ]],
-      [[WHERE   "Someone"]],
-      [[        LIKE     '%YOU%']],
-    })
-    assert.are.same({
-      [[SELECT *]],
-      [[FROM]],
-      [[    World]],
-      [[WHERE]],
-      [[    "Someone"]],
-      [[    LIKE '%YOU%']],
-    }, formatted)
-  end)
-
-  it('can fix', function()
-    local ft = require('guard.filetype')
-    local tool = ft('sql'):fmt('sqlfluff_fix')
-    tool.formatter[1].args = vim.list_extend(tool.formatter[1].args, { '--dialect', 'ansi' })
-
-    local formatted = require('test.formatter.helper').test_with('sql', {
-      [[SELECT]],
-      [[    a + b  AS foo,]],
-      [[    c AS bar]],
-      [[FROM my_table]],
-    })
-    assert.are.same({
-      [[SELECT]],
-      [[    c AS bar,]],
-      [[    a + b AS foo]],
-      [[FROM my_table]],
-    }, formatted)
-  end)
-end)
diff --git a/test/formatter/gofmt_spec.lua b/test/go/gofmt_spec.lua
similarity index 76%
rename from test/formatter/gofmt_spec.lua
rename to test/go/gofmt_spec.lua
index a17d93d..8f3f213 100644
--- a/test/formatter/gofmt_spec.lua
+++ b/test/go/gofmt_spec.lua
@@ -1,9 +1,6 @@
 describe('gofmt', function()
   it('can format', function()
-    local ft = require('guard.filetype')
-    ft('go'):fmt('gofmt')
-
-    local formatted = require('test.formatter.helper').test_with('go', {
+    local formatted = require('test.helper').run_fmt('gofmt', 'go', {
       [[package         main]],
       [[]],
       [[     import   "fmt"     ]],
diff --git a/test/formatter/gofumpt_spec.lua b/test/go/gofumpt_spec.lua
similarity index 76%
rename from test/formatter/gofumpt_spec.lua
rename to test/go/gofumpt_spec.lua
index 933403c..86911ce 100644
--- a/test/formatter/gofumpt_spec.lua
+++ b/test/go/gofumpt_spec.lua
@@ -1,9 +1,6 @@
 describe('gofumpt', function()
   it('can format', function()
-    local ft = require('guard.filetype')
-    ft('go'):fmt('gofumpt')
-
-    local formatted = require('test.formatter.helper').test_with('go', {
+    local formatted = require('test.helper').run_fmt('gofumpt', 'go', {
       [[package         main]],
       [[]],
       [[     import   "fmt"     ]],
diff --git a/test/go/goimports_spec.lua b/test/go/goimports_spec.lua
new file mode 100644
index 0000000..5cbdc1f
--- /dev/null
+++ b/test/go/goimports_spec.lua
@@ -0,0 +1,26 @@
+describe('goimports', function()
+  it('can format', function()
+    local formatted = require('test.helper').run_fmt('goimports', 'go', {
+      [[package main]],
+      [[]],
+      [[import "fmt"]],
+      [[import "os"]],
+      [[]],
+      [[func main() {]],
+      [[fmt.Println(os.Args)]],
+      [[}]],
+    })
+    assert.are.same({
+      [[package main]],
+      [[]],
+      [[import (]],
+      '\t"fmt"',
+      '\t"os"',
+      [[)]],
+      [[]],
+      [[func main() {]],
+      '\tfmt.Println(os.Args)',
+      [[}]],
+    }, formatted)
+  end)
+end)
diff --git a/test/go/golangci_lint_spec.lua b/test/go/golangci_lint_spec.lua
new file mode 100644
index 0000000..aefde3e
--- /dev/null
+++ b/test/go/golangci_lint_spec.lua
@@ -0,0 +1,37 @@
+describe('golangci_lint', function()
+  it('can lint', function()
+    local linter = require('test.helper').get_linter('golangci_lint')
+    local tmpdir = '/tmp/golangci-test'
+    vim.fn.mkdir(tmpdir, 'p')
+    vim.fn.writefile({ 'module test', '', 'go 1.21' }, tmpdir .. '/go.mod')
+    local input = {
+      'package main',
+      '',
+      'import "fmt"',
+      '',
+      'func main() {',
+      '\tfmt.Errorf("unused error")',
+      '}',
+    }
+    vim.fn.writefile(input, tmpdir .. '/main.go')
+    local bufnr = vim.api.nvim_create_buf(false, true)
+    local result = vim
+      .system({
+        'golangci-lint',
+        'run',
+        '--fix=false',
+        '--out-format=json',
+      }, {
+        cwd = tmpdir,
+      })
+      :wait()
+    local output = result.stdout or ''
+    local diagnostics = linter.parse(output, bufnr)
+    assert.is_true(#diagnostics > 0)
+    for _, d in ipairs(diagnostics) do
+      assert.equal(bufnr, d.bufnr)
+      assert.is_number(d.lnum)
+      assert.is_string(d.message)
+    end
+  end)
+end)
diff --git a/test/formatter/golines_spec.lua b/test/go/golines_spec.lua
similarity index 76%
rename from test/formatter/golines_spec.lua
rename to test/go/golines_spec.lua
index 935b61e..0cd4a9b 100644
--- a/test/formatter/golines_spec.lua
+++ b/test/go/golines_spec.lua
@@ -1,9 +1,6 @@
 describe('golines', function()
   it('can format', function()
-    local ft = require('guard.filetype')
-    ft('go'):fmt('golines')
-
-    local formatted = require('test.formatter.helper').test_with('go', {
+    local formatted = require('test.helper').run_fmt('golines', 'go', {
       [[package         main]],
       [[]],
       [[     import   "fmt"     ]],
diff --git a/test/go/yamlfmt_spec.lua b/test/go/yamlfmt_spec.lua
new file mode 100644
index 0000000..8b7bbd9
--- /dev/null
+++ b/test/go/yamlfmt_spec.lua
@@ -0,0 +1,12 @@
+describe('yamlfmt', function()
+  it('can format', function()
+    local formatted = require('test.helper').run_fmt('yamlfmt', 'yaml', {
+      [[name:   John]],
+      [[age:    30]],
+    })
+    assert.are.same({
+      [[name: John]],
+      [[age: 30]],
+    }, formatted)
+  end)
+end)
diff --git a/test/helper.lua b/test/helper.lua
new file mode 100644
index 0000000..e73f168
--- /dev/null
+++ b/test/helper.lua
@@ -0,0 +1,61 @@
+local M = {}
+local api = vim.api
+
+function M.run_fmt(name, ft, input, opts)
+  opts = opts or {}
+  local config = require('guard-collection.formatter')[name]
+  assert(config, 'unknown formatter: ' .. name)
+  assert(not config.fn, name .. ' uses custom fn, not testable this way')
+  local cmd = vim.list_extend({ config.cmd }, config.args or {})
+  local dir = opts.tmpdir or '/tmp'
+  local tmpfile = dir .. '/guard-test.' .. ft
+  if config.fname then
+    vim.fn.writefile(input, tmpfile)
+    table.insert(cmd, tmpfile)
+  end
+  local result = vim
+    .system(cmd, {
+      stdin = config.stdin and (table.concat(input, '\n') .. '\n') or nil,
+      cwd = opts.cwd,
+    })
+    :wait()
+  assert(result.code == 0, name .. ' exited ' .. result.code .. ': ' .. (result.stderr or ''))
+  if config.stdin then
+    return vim.split(result.stdout, '\n', { trimempty = true })
+  else
+    return vim.fn.readfile(tmpfile)
+  end
+end
+
+function M.run_lint(name, ft, input)
+  local linter = require('guard-collection.linter')[name]
+  assert(linter, 'unknown linter: ' .. name)
+  assert(not linter.fn, name .. ' uses custom fn — test parse() directly instead')
+  local input_str = table.concat(input, '\n') .. '\n'
+  local tmpfile = '/tmp/guard-test.' .. ft
+  vim.fn.writefile(input, tmpfile)
+  local bufnr = api.nvim_create_buf(false, true)
+  local cmd = vim.list_extend({ linter.cmd }, linter.args or {})
+  if linter.fname then
+    table.insert(cmd, tmpfile)
+  end
+  local result = vim
+    .system(cmd, {
+      stdin = linter.stdin and input_str or nil,
+    })
+    :wait()
+  local output = result.stdout or ''
+  if output == '' then
+    output = result.stderr or ''
+  end
+  local diags = linter.parse(output, bufnr)
+  return bufnr, diags
+end
+
+function M.get_linter(name)
+  local linter = require('guard-collection.linter')[name]
+  assert(linter, 'unknown linter: ' .. name)
+  return linter
+end
+
+return M
diff --git a/test/linter/buf_spec.lua b/test/linter/buf_spec.lua
deleted file mode 100644
index 7fe56eb..0000000
--- a/test/linter/buf_spec.lua
+++ /dev/null
@@ -1,25 +0,0 @@
-describe('buf', function()
-  it('can lint', function()
-    local helper = require('test.linter.helper')
-    local ns = helper.namespace
-    local ft = require('guard.filetype')
-    ft('proto'):lint('buf')
-
-    local buf, diagnostics = helper.test_with('proto', {
-      [[syntax = "proto3"; message Foo { string bar = 1 }]],
-    })
-    assert.are.same({
-      {
-        bufnr = buf,
-        col = 48,
-        end_col = 48,
-        end_lnum = 0,
-        lnum = 0,
-        message = "syntax error: expecting ';'",
-        namespace = ns,
-        severity = 4,
-        source = 'buf',
-      },
-    }, diagnostics)
-  end)
-end)
diff --git a/test/linter/checkmake_spec.lua b/test/linter/checkmake_spec.lua
deleted file mode 100644
index 2964cd9..0000000
--- a/test/linter/checkmake_spec.lua
+++ /dev/null
@@ -1,48 +0,0 @@
-describe('checkmake', function()
-  it('can lint', function()
-    local helper = require('test.linter.helper')
-    local ns = helper.namespace
-    local ft = require('guard.filetype')
-    ft('make'):lint('checkmake')
-
-    local buf, diagnostics = helper.test_with('make', {
-      [[all:]],
-      [[\techo hello]],
-    })
-    assert.are.same({
-      {
-        bufnr = buf,
-        col = 0,
-        end_col = 0,
-        end_lnum = 0,
-        lnum = 0,
-        message = '[minphony] Missing required phony target "all"',
-        namespace = ns,
-        severity = 2,
-        source = 'checkmake',
-      },
-      {
-        bufnr = buf,
-        col = 0,
-        end_col = 0,
-        end_lnum = 0,
-        lnum = 0,
-        message = '[minphony] Missing required phony target "clean"',
-        namespace = ns,
-        severity = 2,
-        source = 'checkmake',
-      },
-      {
-        bufnr = buf,
-        col = 0,
-        end_col = 0,
-        end_lnum = 0,
-        lnum = 0,
-        message = '[minphony] Missing required phony target "test"',
-        namespace = ns,
-        severity = 2,
-        source = 'checkmake',
-      },
-    }, diagnostics)
-  end)
-end)
diff --git a/test/linter/clang-tidy_spec.lua b/test/linter/clang-tidy_spec.lua
deleted file mode 100644
index 9eee7bd..0000000
--- a/test/linter/clang-tidy_spec.lua
+++ /dev/null
@@ -1,31 +0,0 @@
-describe('clang-tidy', function()
-  it('can lint', function()
-    local helper = require('test.linter.helper')
-    local ns = helper.namespace
-    local ft = require('guard.filetype')
-    ft('c'):lint('clang-tidy')
-
-    local buf, diagnostics = helper.test_with('c', {
-      [[#include <stdio.h>]],
-      [[int main() {]],
-      [[    int x = 10;]],
-      [[    int y = 0;]],
-      [[    printf("%d", x / y);]],
-      [[    return 0;]],
-      [[}]],
-    })
-    assert.are.same({
-      {
-        bufnr = buf,
-        col = 19,
-        end_col = 19,
-        end_lnum = 4,
-        lnum = 4,
-        message = 'Division by zero[clang-analyzer-core.DivideZero]',
-        namespace = ns,
-        severity = 2,
-        source = 'clang-tidy',
-      },
-    }, diagnostics)
-  end)
-end)
diff --git a/test/linter/flake8_spec.lua b/test/linter/flake8_spec.lua
deleted file mode 100644
index e12b780..0000000
--- a/test/linter/flake8_spec.lua
+++ /dev/null
@@ -1,107 +0,0 @@
-describe('flake8', function()
-  it('can lint', function()
-    local helper = require('test.linter.helper')
-    local ns = helper.namespace
-    local ft = require('guard.filetype')
-    ft('python'):lint('flake8')
-
-    local buf, diagnostics = helper.test_with('python', {
-      [[import os]],
-      [[]],
-      [[def foo(n):]],
-      [[    if n == 0:]],
-      [[         return  bar]],
-      [[print("it's too long sentence to be displayed in one line, blah blah blah blah")]],
-    })
-    assert.are.same({
-      {
-        bufnr = buf,
-        col = 0,
-        end_col = 0,
-        end_lnum = 0,
-        lnum = 0,
-        message = "'os' imported but unused[401]",
-        namespace = ns,
-        severity = 3,
-        source = 'flake8',
-      },
-      {
-        bufnr = buf,
-        col = 0,
-        end_col = 0,
-        end_lnum = 2,
-        lnum = 2,
-        message = 'expected 2 blank lines, found 1[302]',
-        namespace = ns,
-        severity = 1,
-        source = 'flake8',
-      },
-      {
-        bufnr = buf,
-        col = 9,
-        end_col = 9,
-        end_lnum = 4,
-        lnum = 4,
-        message = 'indentation is not a multiple of 4[111]',
-        namespace = ns,
-        severity = 1,
-        source = 'flake8',
-      },
-      {
-        bufnr = buf,
-        col = 9,
-        end_col = 9,
-        end_lnum = 4,
-        lnum = 4,
-        message = 'over-indented[117]',
-        namespace = ns,
-        severity = 1,
-        source = 'flake8',
-      },
-      {
-        bufnr = buf,
-        col = 15,
-        end_col = 15,
-        end_lnum = 4,
-        lnum = 4,
-        message = 'multiple spaces after keyword[271]',
-        namespace = ns,
-        severity = 1,
-        source = 'flake8',
-      },
-      {
-        bufnr = buf,
-        col = 17,
-        end_col = 17,
-        end_lnum = 4,
-        lnum = 4,
-        message = "undefined name 'bar'[821]",
-        namespace = ns,
-        severity = 3,
-        source = 'flake8',
-      },
-      {
-        bufnr = buf,
-        col = 0,
-        end_col = 0,
-        end_lnum = 5,
-        lnum = 5,
-        message = 'expected 2 blank lines after class or function definition, found 0[305]',
-        namespace = ns,
-        severity = 1,
-        source = 'flake8',
-      },
-      {
-        bufnr = buf,
-        col = 79,
-        end_col = 79,
-        end_lnum = 5,
-        lnum = 5,
-        message = 'line too long (80 > 79 characters)[501]',
-        namespace = ns,
-        severity = 1,
-        source = 'flake8',
-      },
-    }, diagnostics)
-  end)
-end)
diff --git a/test/linter/helper.lua b/test/linter/helper.lua
deleted file mode 100644
index fb43a42..0000000
--- a/test/linter/helper.lua
+++ /dev/null
@@ -1,22 +0,0 @@
-local M = {}
-local api = vim.api
-local lint = require('guard.lint')
-M.namespace = api.nvim_get_namespaces().Guard
-
-function M.test_with(ft, input)
-  local cmd = require('guard.filetype')(ft).linter[1].cmd
-  assert(vim.fn.executable(cmd) == 1)
-
-  local bufnr = api.nvim_create_buf(true, false)
-  vim.bo[bufnr].filetype = ft
-  api.nvim_set_current_buf(bufnr)
-  api.nvim_buf_set_lines(bufnr, 0, -1, false, input)
-  -- To make linters happy
-  vim.cmd('silent! write! /tmp/test.' .. ft)
-
-  lint.do_lint(bufnr)
-  vim.wait(3000)
-  return bufnr, vim.diagnostic.get(bufnr)
-end
-
-return M
diff --git a/test/linter/hlint_spec.lua b/test/linter/hlint_spec.lua
deleted file mode 100644
index 02864da..0000000
--- a/test/linter/hlint_spec.lua
+++ /dev/null
@@ -1,49 +0,0 @@
-describe('hlint', function()
-  it('can lint', function()
-    local helper = require('test.linter.helper')
-    local ns = helper.namespace
-    local ft = require('guard.filetype')
-    ft('haskell'):lint('hlint')
-
-    local buf, diagnostics = helper.test_with('haskell', {
-      [[concat $ map escapeC s]],
-      [[ftable ++ (map (\ (c, x) -> (toUpper c, urlEncode x)) ftable)]],
-      [[mapM (delete_line (fn2fp f) line) old]],
-    })
-    assert.are.same({
-      {
-        bufnr = buf,
-        col = 0,
-        end_col = 0,
-        end_lnum = 0,
-        lnum = 0,
-        message = 'Use concatMap: concatMap escapeC s',
-        namespace = ns,
-        severity = 2,
-        source = 'hlint',
-      },
-      {
-        bufnr = buf,
-        col = 10,
-        end_col = 10,
-        end_lnum = 1,
-        lnum = 1,
-        message = [[Redundant bracket: ftable ++ map (\ (c, x) -> (toUpper c, urlEncode x)) ftable]],
-        namespace = ns,
-        severity = 3,
-        source = 'hlint',
-      },
-      {
-        bufnr = buf,
-        col = 16,
-        end_col = 16,
-        end_lnum = 1,
-        lnum = 1,
-        message = 'Use bimap: Data.Bifunctor.bimap toUpper urlEncode',
-        namespace = ns,
-        severity = 3,
-        source = 'hlint',
-      },
-    }, diagnostics)
-  end)
-end)
diff --git a/test/linter/luacheck_spec.lua b/test/linter/luacheck_spec.lua
deleted file mode 100644
index 0731c74..0000000
--- a/test/linter/luacheck_spec.lua
+++ /dev/null
@@ -1,30 +0,0 @@
-describe('luacheck', function()
-  it('can lint', function()
-    local helper = require('test.linter.helper')
-    local ns = helper.namespace
-    local ft = require('guard.filetype')
-    ft('lua'):lint('luacheck')
-
-    local buf, diagnostics = helper.test_with('lua', {
-      [[local M = {}]],
-      [[function M.foo()]],
-      [[  print("foo")]],
-      [[end]],
-      [[U.bar()]],
-      [[return M]],
-    })
-    assert.are.same({
-      {
-        bufnr = buf,
-        col = 0,
-        end_col = 0,
-        end_lnum = 4,
-        lnum = 4,
-        message = "accessing undefined variable 'U'[113]",
-        namespace = ns,
-        severity = 2,
-        source = 'luacheck',
-      },
-    }, diagnostics)
-  end)
-end)
diff --git a/test/linter/selene_spec.lua b/test/linter/selene_spec.lua
deleted file mode 100644
index 9be18f9..0000000
--- a/test/linter/selene_spec.lua
+++ /dev/null
@@ -1,25 +0,0 @@
-describe('selene', function()
-  it('can lint', function()
-    local helper = require('test.linter.helper')
-    local ns = helper.namespace
-    local ft = require('guard.filetype')
-    ft('lua'):lint('selene')
-
-    local buf, diagnostics = helper.test_with('lua', {
-      [[print(a)]],
-    })
-    assert.are.same({
-      {
-        bufnr = buf,
-        col = 6,
-        end_col = 0,
-        end_lnum = 0,
-        lnum = 0,
-        message = '`a` is not defined[undefined_variable]',
-        namespace = ns,
-        severity = 1,
-        source = 'selene',
-      },
-    }, diagnostics)
-  end)
-end)
diff --git a/test/lua/fnlfmt_spec.lua b/test/lua/fnlfmt_spec.lua
new file mode 100644
index 0000000..2173e44
--- /dev/null
+++ b/test/lua/fnlfmt_spec.lua
@@ -0,0 +1,10 @@
+describe('fnlfmt', function()
+  it('can format', function()
+    local formatted = require('test.helper').run_fmt('fnlfmt', 'fnl', {
+      [[(fn hello []  (print "hello"]],
+      [[))]],
+    })
+    assert.is_true(#formatted > 0)
+    assert.is_true(formatted[1]:find('fn hello') ~= nil)
+  end)
+end)
diff --git a/test/lua/luacheck_spec.lua b/test/lua/luacheck_spec.lua
new file mode 100644
index 0000000..e043ea7
--- /dev/null
+++ b/test/lua/luacheck_spec.lua
@@ -0,0 +1,20 @@
+describe('luacheck', function()
+  it('can lint', function()
+    local helper = require('test.helper')
+    local buf, diagnostics = helper.run_lint('luacheck', 'lua', {
+      [[local M = {}]],
+      [[function M.foo()]],
+      [[  print("foo")]],
+      [[end]],
+      [[U.bar()]],
+      [[return M]],
+    })
+    assert.is_true(#diagnostics > 0)
+    for _, d in ipairs(diagnostics) do
+      assert.equal(buf, d.bufnr)
+      assert.equal('luacheck', d.source)
+      assert.is_number(d.lnum)
+      assert.is_string(d.message)
+    end
+  end)
+end)
diff --git a/test/lua/selene_spec.lua b/test/lua/selene_spec.lua
new file mode 100644
index 0000000..04d25d5
--- /dev/null
+++ b/test/lua/selene_spec.lua
@@ -0,0 +1,15 @@
+describe('selene', function()
+  it('can lint', function()
+    local helper = require('test.helper')
+    local buf, diagnostics = helper.run_lint('selene', 'lua', {
+      [[print(a)]],
+    })
+    assert.is_true(#diagnostics > 0)
+    for _, d in ipairs(diagnostics) do
+      assert.equal(buf, d.bufnr)
+      assert.equal('selene', d.source)
+      assert.is_number(d.lnum)
+      assert.is_string(d.message)
+    end
+  end)
+end)
diff --git a/test/formatter/stylua_spec.lua b/test/lua/stylua_spec.lua
similarity index 65%
rename from test/formatter/stylua_spec.lua
rename to test/lua/stylua_spec.lua
index a98d5b1..0e2b054 100644
--- a/test/formatter/stylua_spec.lua
+++ b/test/lua/stylua_spec.lua
@@ -1,9 +1,6 @@
 describe('stylua', function()
   it('can format', function()
-    local ft = require('guard.filetype')
-    ft('lua'):fmt('stylua')
-
-    local formatted = require('test.formatter.helper').test_with('lua', {
+    local formatted = require('test.helper').run_fmt('stylua', 'lua', {
       [[local M={}]],
       [[   M.foo  =]],
       [[  "foo"]],
diff --git a/test/nix/nixfmt_spec.lua b/test/nix/nixfmt_spec.lua
new file mode 100644
index 0000000..254d631
--- /dev/null
+++ b/test/nix/nixfmt_spec.lua
@@ -0,0 +1,9 @@
+describe('nixfmt', function()
+  it('can format', function()
+    local formatted = require('test.helper').run_fmt('nixfmt', 'nix', {
+      [[{pkgs,...}:{environment.systemPackages=[pkgs.vim];}]],
+    })
+    assert.is_true(#formatted > 0)
+    assert.is_true(formatted[1]:find('pkgs') ~= nil)
+  end)
+end)
diff --git a/test/formatter/biome_spec.lua b/test/npm/biome_spec.lua
similarity index 67%
rename from test/formatter/biome_spec.lua
rename to test/npm/biome_spec.lua
index dedb733..a697946 100644
--- a/test/formatter/biome_spec.lua
+++ b/test/npm/biome_spec.lua
@@ -1,9 +1,6 @@
 describe('biome', function()
   it('can format json', function()
-    local ft = require('guard.filetype')
-    ft('json'):fmt('biome')
-
-    local formatted = require('test.formatter.helper').test_with('json', {
+    local formatted = require('test.helper').run_fmt('biome', 'json', {
       [[{"name":   "dove" , "age":10 ]],
       [[,"gender":   "male"}]],
     })
@@ -13,10 +10,7 @@ describe('biome', function()
   end)
 
   it('can format javascript', function()
-    local ft = require('guard.filetype')
-    ft('js'):fmt('biome')
-
-    local formatted = require('test.formatter.helper').test_with('js', {
+    local formatted = require('test.helper').run_fmt('biome', 'js', {
       [[            const randomNumber = Math.floor(]],
       [[      Math.random() *           10]],
       [[      ) + 1]],
diff --git a/test/npm/eslint_d_spec.lua b/test/npm/eslint_d_spec.lua
new file mode 100644
index 0000000..f8a4893
--- /dev/null
+++ b/test/npm/eslint_d_spec.lua
@@ -0,0 +1,66 @@
+describe('eslint_d', function()
+  it('can lint', function()
+    local linter = require('test.helper').get_linter('eslint_d')
+    local tmpdir = '/tmp/eslintd-test'
+    vim.fn.mkdir(tmpdir, 'p')
+    vim.fn.writefile({
+      'module.exports = [{ rules: { "no-unused-vars": "error" } }];',
+    }, tmpdir .. '/eslint.config.js')
+    local tmpfile = tmpdir .. '/test.js'
+    local input = {
+      [[const x = 1;]],
+    }
+    vim.fn.writefile(input, tmpfile)
+    local bufnr = vim.api.nvim_create_buf(false, true)
+    local result = vim
+      .system({
+        'npx',
+        'eslint_d',
+        '--format',
+        'json',
+        '--stdin',
+        '--stdin-filename',
+        tmpfile,
+      }, {
+        stdin = table.concat(input, '\n') .. '\n',
+        cwd = tmpdir,
+      })
+      :wait()
+    local output = result.stdout or ''
+    local diagnostics = linter.parse(output, bufnr)
+    assert.is_true(#diagnostics > 0)
+    for _, d in ipairs(diagnostics) do
+      assert.equal(bufnr, d.bufnr)
+      assert.equal('eslint_d', d.source)
+      assert.is_number(d.lnum)
+      assert.is_string(d.message)
+    end
+  end)
+
+  it('can format', function()
+    local tmpdir = '/tmp/eslintd-test'
+    vim.fn.mkdir(tmpdir, 'p')
+    vim.fn.writefile({
+      'module.exports = [{ rules: { "semi": ["error", "always"] } }];',
+    }, tmpdir .. '/eslint.config.js')
+    local tmpfile = tmpdir .. '/test.js'
+    local input = {
+      [[const x = 1]],
+    }
+    vim.fn.writefile(input, tmpfile)
+    local config = require('guard-collection.formatter').eslint_d
+    local cmd = vim.list_extend({ config.cmd }, config.args)
+    table.insert(cmd, tmpfile)
+    local result = vim
+      .system(cmd, {
+        stdin = table.concat(input, '\n') .. '\n',
+        cwd = tmpdir,
+      })
+      :wait()
+    assert(result.code == 0, 'eslint_d exited ' .. result.code .. ': ' .. (result.stderr or ''))
+    local formatted = vim.split(result.stdout, '\n', { trimempty = true })
+    assert.are.same({
+      [[const x = 1;]],
+    }, formatted)
+  end)
+end)
diff --git a/test/npm/eslint_spec.lua b/test/npm/eslint_spec.lua
new file mode 100644
index 0000000..8ea0339
--- /dev/null
+++ b/test/npm/eslint_spec.lua
@@ -0,0 +1,39 @@
+describe('eslint', function()
+  it('can lint', function()
+    local linter = require('test.helper').get_linter('eslint')
+    local tmpdir = '/tmp/eslint-test'
+    vim.fn.mkdir(tmpdir, 'p')
+    vim.fn.writefile({
+      'module.exports = [{ rules: { "no-unused-vars": "error" } }];',
+    }, tmpdir .. '/eslint.config.js')
+    local tmpfile = tmpdir .. '/test.js'
+    local input = {
+      [[const x = 1;]],
+    }
+    vim.fn.writefile(input, tmpfile)
+    local bufnr = vim.api.nvim_create_buf(false, true)
+    local result = vim
+      .system({
+        'npx',
+        'eslint',
+        '--format',
+        'json',
+        '--stdin',
+        '--stdin-filename',
+        tmpfile,
+      }, {
+        stdin = table.concat(input, '\n') .. '\n',
+        cwd = tmpdir,
+      })
+      :wait()
+    local output = result.stdout or ''
+    local diagnostics = linter.parse(output, bufnr)
+    assert.is_true(#diagnostics > 0)
+    for _, d in ipairs(diagnostics) do
+      assert.equal(bufnr, d.bufnr)
+      assert.equal('eslint', d.source)
+      assert.is_number(d.lnum)
+      assert.is_string(d.message)
+    end
+  end)
+end)
diff --git a/test/formatter/prettier_spec.lua b/test/npm/prettier_spec.lua
similarity index 70%
rename from test/formatter/prettier_spec.lua
rename to test/npm/prettier_spec.lua
index aa381af..2be27a7 100644
--- a/test/formatter/prettier_spec.lua
+++ b/test/npm/prettier_spec.lua
@@ -1,9 +1,6 @@
 describe('prettier', function()
   it('can format', function()
-    local ft = require('guard.filetype')
-    ft('javascript'):fmt('prettier')
-
-    local formatted = require('test.formatter.helper').test_with('javascript', {
+    local formatted = require('test.helper').run_fmt('prettier', 'javascript', {
       [[            const randomNumber = Math.floor(]],
       [[      Math.random() *           10]],
       [[      ) + 1]],
diff --git a/test/npm/prettierd_spec.lua b/test/npm/prettierd_spec.lua
new file mode 100644
index 0000000..61cecd6
--- /dev/null
+++ b/test/npm/prettierd_spec.lua
@@ -0,0 +1,20 @@
+describe('prettierd', function()
+  it('can format', function()
+    local tmpfile = '/tmp/guard-test.js'
+    local input = {
+      'const x={a:1,b:2,c:3}',
+      'const y = [1,2,3,4,5]',
+    }
+    vim.fn.writefile(input, tmpfile)
+    local result = vim
+      .system({ 'prettierd', tmpfile }, { stdin = table.concat(input, '\n') })
+      :wait()
+    assert.equal(0, result.code)
+    local expected = table.concat({
+      'const x = { a: 1, b: 2, c: 3 };',
+      'const y = [1, 2, 3, 4, 5];',
+      '',
+    }, '\n')
+    assert.equal(expected, result.stdout)
+  end)
+end)
diff --git a/test/formatter/sql-formatter_spec.lua b/test/npm/sql-formatter_spec.lua
similarity index 66%
rename from test/formatter/sql-formatter_spec.lua
rename to test/npm/sql-formatter_spec.lua
index 2063998..7d03101 100644
--- a/test/formatter/sql-formatter_spec.lua
+++ b/test/npm/sql-formatter_spec.lua
@@ -1,9 +1,6 @@
 describe('sql-formatter', function()
   it('can format', function()
-    local ft = require('guard.filetype')
-    ft('sql'):fmt('sql-formatter')
-
-    local formatted = require('test.formatter.helper').test_with('sql', {
+    local formatted = require('test.helper').run_fmt('sql-formatter', 'sql', {
       [[SELECT          *]],
       [[FROM]],
       [[World]],
@@ -17,8 +14,6 @@ describe('sql-formatter', function()
       [[  World]],
       [[WHERE]],
       [[  "Someone" LIKE '%YOU%']],
-      -- /> no results!
-      -- /> :sob
     }, formatted)
   end)
 end)
diff --git a/test/npm/stylelint_spec.lua b/test/npm/stylelint_spec.lua
new file mode 100644
index 0000000..70639c1
--- /dev/null
+++ b/test/npm/stylelint_spec.lua
@@ -0,0 +1,46 @@
+describe('stylelint', function()
+  it('can lint', function()
+    local linter = require('test.helper').get_linter('stylelint')
+    local tmpdir = '/tmp/stylelint-test'
+    vim.fn.mkdir(tmpdir, 'p')
+    local configfile = tmpdir .. '/.stylelintrc.json'
+    vim.fn.writefile({
+      '{ "rules": { "color-no-invalid-hex": true } }',
+    }, configfile)
+    local tmpfile = tmpdir .. '/test.css'
+    local input = {
+      [[a { color: #fff1az; }]],
+    }
+    vim.fn.writefile(input, tmpfile)
+    local bufnr = vim.api.nvim_create_buf(false, true)
+    local result = vim
+      .system({
+        'npx',
+        'stylelint',
+        '--formatter',
+        'json',
+        '--stdin',
+        '--stdin-filename',
+        tmpfile,
+        '--config',
+        configfile,
+      }, {
+        stdin = table.concat(input, '\n') .. '\n',
+        cwd = tmpdir,
+      })
+      :wait()
+    local output = result.stdout or ''
+    if output == '' then
+      output = result.stderr or ''
+    end
+    assert(output ~= '', 'stylelint: no output (code=' .. result.code .. ')')
+    local diagnostics = linter.parse(output, bufnr)
+    assert.is_true(#diagnostics > 0)
+    for _, d in ipairs(diagnostics) do
+      assert.equal(bufnr, d.bufnr)
+      assert.equal('stylelint', d.source)
+      assert.is_number(d.lnum)
+      assert.is_string(d.message)
+    end
+  end)
+end)
diff --git a/test/formatter/taplo_spec.lua b/test/npm/taplo_spec.lua
similarity index 79%
rename from test/formatter/taplo_spec.lua
rename to test/npm/taplo_spec.lua
index bdada26..d92bec6 100644
--- a/test/formatter/taplo_spec.lua
+++ b/test/npm/taplo_spec.lua
@@ -1,9 +1,6 @@
 describe('taplo', function()
   it('can format', function()
-    local ft = require('guard.filetype')
-    ft('toml'):fmt('taplo')
-
-    local formatted = require('test.formatter.helper').test_with('toml', {
+    local formatted = require('test.helper').run_fmt('taplo', 'toml', {
       [[        [dependencies]        ]],
       [[           async-process = "^1.7"]],
       [[strum = {       version = "^0.25",   features = ["derive"]       } ]],
diff --git a/test/formatter/autopep8_spec.lua b/test/pip/autopep8_spec.lua
similarity index 78%
rename from test/formatter/autopep8_spec.lua
rename to test/pip/autopep8_spec.lua
index 7f89f4a..3e96edf 100644
--- a/test/formatter/autopep8_spec.lua
+++ b/test/pip/autopep8_spec.lua
@@ -1,9 +1,6 @@
 describe('autopep8', function()
   it('can format', function()
-    local ft = require('guard.filetype')
-    ft('python'):fmt('autopep8')
-
-    local formatted = require('test.formatter.helper').test_with('python', {
+    local formatted = require('test.helper').run_fmt('autopep8', 'python', {
       [[def foo(n):]],
       [[    if n in         (1,2,3):]],
       [[        return n+1]],
diff --git a/test/formatter/black_spec.lua b/test/pip/black_spec.lua
similarity index 78%
rename from test/formatter/black_spec.lua
rename to test/pip/black_spec.lua
index 2312e76..1deffcd 100644
--- a/test/formatter/black_spec.lua
+++ b/test/pip/black_spec.lua
@@ -1,9 +1,6 @@
 describe('black', function()
   it('can format', function()
-    local ft = require('guard.filetype')
-    ft('python'):fmt('black')
-
-    local formatted = require('test.formatter.helper').test_with('python', {
+    local formatted = require('test.helper').run_fmt('black', 'python', {
       [[def foo(n):]],
       [[    if n in         (1,2,3):]],
       [[        return n+1]],
diff --git a/test/formatter/cmake-format_spec.lua b/test/pip/cmake-format_spec.lua
similarity index 69%
rename from test/formatter/cmake-format_spec.lua
rename to test/pip/cmake-format_spec.lua
index 2e5a817..25af6e5 100644
--- a/test/formatter/cmake-format_spec.lua
+++ b/test/pip/cmake-format_spec.lua
@@ -1,9 +1,6 @@
 describe('cmake-format', function()
   it('can format', function()
-    local ft = require('guard.filetype')
-    ft('cmake'):fmt('cmake-format')
-
-    local formatted = require('test.formatter.helper').test_with('cmake', {
+    local formatted = require('test.helper').run_fmt('cmake-format', 'cmake', {
       [[cmake_minimum_required(VERSION 3.10)]],
       [[project(test)]],
       [[add_executable(test main.cpp)]],
diff --git a/test/pip/codespell_spec.lua b/test/pip/codespell_spec.lua
new file mode 100644
index 0000000..b16fdc1
--- /dev/null
+++ b/test/pip/codespell_spec.lua
@@ -0,0 +1,15 @@
+describe('codespell', function()
+  it('can lint', function()
+    local helper = require('test.helper')
+    local buf, diagnostics = helper.run_lint('codespell', 'txt', {
+      [[teh quick brown fox]],
+    })
+    assert.is_true(#diagnostics > 0)
+    for _, d in ipairs(diagnostics) do
+      assert.equal(buf, d.bufnr)
+      assert.equal('codespell', d.source)
+      assert.is_number(d.lnum)
+      assert.is_string(d.message)
+    end
+  end)
+end)
diff --git a/test/pip/cpplint_spec.lua b/test/pip/cpplint_spec.lua
new file mode 100644
index 0000000..cb0095a
--- /dev/null
+++ b/test/pip/cpplint_spec.lua
@@ -0,0 +1,19 @@
+describe('cpplint', function()
+  it('can lint', function()
+    local linter = require('test.helper').get_linter('cpplint')
+    local tmpfile = '/tmp/guard-test.cpp'
+    local input = { [[int main(){int x=1;}]] }
+    vim.fn.writefile(input, tmpfile)
+    local bufnr = vim.api.nvim_create_buf(false, true)
+    local result = vim.system({ 'cpplint', '--filter=-legal/copyright', tmpfile }, {}):wait()
+    local output = result.stderr or ''
+    local diagnostics = linter.parse(output, bufnr)
+    assert.is_true(#diagnostics > 0)
+    for _, d in ipairs(diagnostics) do
+      assert.equal(bufnr, d.bufnr)
+      assert.equal('cpplint', d.source)
+      assert.is_number(d.lnum)
+      assert.is_string(d.message)
+    end
+  end)
+end)
diff --git a/test/pip/djhtml_spec.lua b/test/pip/djhtml_spec.lua
new file mode 100644
index 0000000..32529b1
--- /dev/null
+++ b/test/pip/djhtml_spec.lua
@@ -0,0 +1,14 @@
+describe('djhtml', function()
+  it('can format', function()
+    local formatted = require('test.helper').run_fmt('djhtml', 'html', {
+      [[<div>]],
+      [[<p>hello</p>]],
+      [[</div>]],
+    })
+    assert.are.same({
+      [[<div>]],
+      [[    <p>hello</p>]],
+      [[</div>]],
+    }, formatted)
+  end)
+end)
diff --git a/test/formatter/docformatter_spec.lua b/test/pip/docformatter_spec.lua
similarity index 69%
rename from test/formatter/docformatter_spec.lua
rename to test/pip/docformatter_spec.lua
index 977d80d..1871572 100644
--- a/test/formatter/docformatter_spec.lua
+++ b/test/pip/docformatter_spec.lua
@@ -1,9 +1,6 @@
 describe('docformatter', function()
   it('can format', function()
-    local ft = require('guard.filetype')
-    ft('python'):fmt('docformatter')
-
-    local formatted = require('test.formatter.helper').test_with('python', {
+    local formatted = require('test.helper').run_fmt('docformatter', 'python', {
       [[def foo():]],
       [[    """]],
       [[    Hello foo.]],
diff --git a/test/pip/flake8_spec.lua b/test/pip/flake8_spec.lua
new file mode 100644
index 0000000..fab866a
--- /dev/null
+++ b/test/pip/flake8_spec.lua
@@ -0,0 +1,21 @@
+describe('flake8', function()
+  it('can lint', function()
+    local helper = require('test.helper')
+    local buf, diagnostics = helper.run_lint('flake8', 'python', {
+      [[import os]],
+      [[]],
+      [[def foo(n):]],
+      [[    if n == 0:]],
+      [[         return  bar]],
+      [[print("it's too long sentence to be displayed in one line, blah blah blah blah")]],
+    })
+    assert.is_true(#diagnostics > 0)
+    for _, d in ipairs(diagnostics) do
+      assert.equal(buf, d.bufnr)
+      assert.equal('flake8', d.source)
+      assert.is_number(d.lnum)
+      assert.is_number(d.col)
+      assert.is_string(d.message)
+    end
+  end)
+end)
diff --git a/test/pip/isort_spec.lua b/test/pip/isort_spec.lua
new file mode 100644
index 0000000..b91a95e
--- /dev/null
+++ b/test/pip/isort_spec.lua
@@ -0,0 +1,14 @@
+describe('isort', function()
+  it('can format', function()
+    local formatted = require('test.helper').run_fmt('isort', 'python', {
+      [[import sys]],
+      [[import os]],
+      [[import json]],
+    })
+    assert.are.same({
+      [[import json]],
+      [[import os]],
+      [[import sys]],
+    }, formatted)
+  end)
+end)
diff --git a/test/pip/mdformat_spec.lua b/test/pip/mdformat_spec.lua
new file mode 100644
index 0000000..f30a03c
--- /dev/null
+++ b/test/pip/mdformat_spec.lua
@@ -0,0 +1,13 @@
+describe('mdformat', function()
+  it('can format', function()
+    local formatted = require('test.helper').run_fmt('mdformat', 'markdown', {
+      [[#   title]],
+      [[text]],
+    })
+    assert.are.same({
+      [[# title]],
+      [[]],
+      [[text]],
+    }, formatted)
+  end)
+end)
diff --git a/test/pip/mypy_spec.lua b/test/pip/mypy_spec.lua
new file mode 100644
index 0000000..40fa9a9
--- /dev/null
+++ b/test/pip/mypy_spec.lua
@@ -0,0 +1,29 @@
+describe('mypy', function()
+  it('can lint', function()
+    local linter = require('test.helper').get_linter('mypy')
+    local tmpfile = '/tmp/guard-test.py'
+    local input = {
+      'def add(x: int, y: int) -> int:',
+      '    return x + y',
+      '',
+      'add("hello", "world")',
+    }
+    vim.fn.writefile(input, tmpfile)
+    local bufnr = vim.api.nvim_create_buf(false, true)
+    local cmd = vim.list_extend({ linter.cmd }, linter.args or {})
+    table.insert(cmd, tmpfile)
+    local result = vim.system(cmd):wait()
+    local output = result.stdout or ''
+    if output == '' then
+      output = result.stderr or ''
+    end
+    local diagnostics = linter.parse(output, bufnr)
+    assert.is_true(#diagnostics > 0)
+    for _, d in ipairs(diagnostics) do
+      assert.equal(bufnr, d.bufnr)
+      assert.equal('mypy', d.source)
+      assert.is_number(d.lnum)
+      assert.is_string(d.message)
+    end
+  end)
+end)
diff --git a/test/pip/mypyc_spec.lua b/test/pip/mypyc_spec.lua
new file mode 100644
index 0000000..850fd33
--- /dev/null
+++ b/test/pip/mypyc_spec.lua
@@ -0,0 +1,29 @@
+describe('mypyc', function()
+  it('can lint', function()
+    local linter = require('test.helper').get_linter('mypyc')
+    local tmpfile = '/tmp/guard-test.py'
+    local input = {
+      'def add(x: int, y: int) -> int:',
+      '    return x + y',
+      '',
+      'add("hello", "world")',
+    }
+    vim.fn.writefile(input, tmpfile)
+    local bufnr = vim.api.nvim_create_buf(false, true)
+    local cmd = vim.list_extend({ linter.cmd }, linter.args or {})
+    table.insert(cmd, tmpfile)
+    local result = vim.system(cmd):wait()
+    local output = result.stdout or ''
+    if output == '' then
+      output = result.stderr or ''
+    end
+    local diagnostics = linter.parse(output, bufnr)
+    assert.is_true(#diagnostics > 0)
+    for _, d in ipairs(diagnostics) do
+      assert.equal(bufnr, d.bufnr)
+      assert.equal('mypy', d.source)
+      assert.is_number(d.lnum)
+      assert.is_string(d.message)
+    end
+  end)
+end)
diff --git a/test/pip/pylint_spec.lua b/test/pip/pylint_spec.lua
new file mode 100644
index 0000000..54bf7ae
--- /dev/null
+++ b/test/pip/pylint_spec.lua
@@ -0,0 +1,32 @@
+describe('pylint', function()
+  it('can lint', function()
+    local linter = require('test.helper').get_linter('pylint')
+    local tmpfile = '/tmp/guard-test.py'
+    local input = {
+      [[import os]],
+      [[x = 1]],
+    }
+    vim.fn.writefile(input, tmpfile)
+    local bufnr = vim.api.nvim_create_buf(false, true)
+    local result = vim
+      .system({
+        'pylint',
+        '--from-stdin',
+        '--output-format',
+        'json',
+        tmpfile,
+      }, {
+        stdin = table.concat(input, '\n') .. '\n',
+      })
+      :wait()
+    local output = result.stdout or ''
+    local diagnostics = linter.parse(output, bufnr)
+    assert.is_true(#diagnostics > 0)
+    for _, d in ipairs(diagnostics) do
+      assert.equal(bufnr, d.bufnr)
+      assert.equal('pylint', d.source)
+      assert.is_number(d.lnum)
+      assert.is_string(d.message)
+    end
+  end)
+end)
diff --git a/test/pip/ruff_fix_spec.lua b/test/pip/ruff_fix_spec.lua
new file mode 100644
index 0000000..91c862b
--- /dev/null
+++ b/test/pip/ruff_fix_spec.lua
@@ -0,0 +1,15 @@
+describe('ruff_fix', function()
+  it('can format', function()
+    local formatted = require('test.helper').run_fmt('ruff_fix', 'py', {
+      [[import os]],
+      [[import sys]],
+      [[]],
+      [[print(sys.argv)]],
+    })
+    assert.are.same({
+      [[import sys]],
+      [[]],
+      [[print(sys.argv)]],
+    }, formatted)
+  end)
+end)
diff --git a/test/formatter/ruff_spec.lua b/test/pip/ruff_spec.lua
similarity index 52%
rename from test/formatter/ruff_spec.lua
rename to test/pip/ruff_spec.lua
index 11dcb07..8439bd0 100644
--- a/test/formatter/ruff_spec.lua
+++ b/test/pip/ruff_spec.lua
@@ -1,9 +1,6 @@
 describe('ruff', function()
   it('can format', function()
-    local ft = require('guard.filetype')
-    ft('python'):fmt('ruff')
-
-    local formatted = require('test.formatter.helper').test_with('python', {
+    local formatted = require('test.helper').run_fmt('ruff', 'python', {
       [[def foo(n):]],
       [[    if n in         (1,2,3):]],
       [[        return n+1]],
@@ -22,4 +19,19 @@ describe('ruff', function()
       [[print(f"The factorial of {a} is: {foo(a)}")]],
     }, formatted)
   end)
+
+  it('can lint', function()
+    local helper = require('test.helper')
+    local buf, diagnostics = helper.run_lint('ruff', 'py', {
+      [[import os]],
+      [[x = 1]],
+    })
+    assert.is_true(#diagnostics > 0)
+    for _, d in ipairs(diagnostics) do
+      assert.equal(buf, d.bufnr)
+      assert.equal('ruff', d.source)
+      assert.is_number(d.lnum)
+      assert.is_string(d.message)
+    end
+  end)
 end)
diff --git a/test/pip/sqlfluff_spec.lua b/test/pip/sqlfluff_spec.lua
new file mode 100644
index 0000000..cb8452b
--- /dev/null
+++ b/test/pip/sqlfluff_spec.lua
@@ -0,0 +1,54 @@
+describe('sqlfluff', function()
+  it('can format', function()
+    local config = require('guard-collection.formatter').sqlfluff
+    local cmd = vim.list_extend({ config.cmd }, config.args)
+    vim.list_extend(cmd, { '--dialect', 'ansi' })
+    local input = {
+      [[SELECT          *]],
+      [[FROM]],
+      [[         World         ]],
+      [[WHERE   "Someone"]],
+      [[        LIKE     '%YOU%']],
+    }
+    local result = vim
+      .system(cmd, {
+        stdin = table.concat(input, '\n') .. '\n',
+      })
+      :wait()
+    assert(result.code == 0, 'sqlfluff exited ' .. result.code .. ': ' .. (result.stderr or ''))
+    local formatted = vim.split(result.stdout, '\n', { trimempty = true })
+    assert.are.same({
+      [[SELECT *]],
+      [[FROM]],
+      [[    World]],
+      [[WHERE]],
+      [[    "Someone"]],
+      [[    LIKE '%YOU%']],
+    }, formatted)
+  end)
+
+  it('can fix', function()
+    local config = require('guard-collection.formatter').sqlfluff_fix
+    local cmd = vim.list_extend({ config.cmd }, config.args)
+    vim.list_extend(cmd, { '--dialect', 'ansi' })
+    local input = {
+      [[SELECT]],
+      [[    a + b  AS foo,]],
+      [[    c AS bar]],
+      [[FROM my_table]],
+    }
+    local result = vim
+      .system(cmd, {
+        stdin = table.concat(input, '\n') .. '\n',
+      })
+      :wait()
+    assert(result.code == 0, 'sqlfluff_fix exited ' .. result.code .. ': ' .. (result.stderr or ''))
+    local formatted = vim.split(result.stdout, '\n', { trimempty = true })
+    assert.are.same({
+      [[SELECT]],
+      [[    c AS bar,]],
+      [[    a + b AS foo]],
+      [[FROM my_table]],
+    }, formatted)
+  end)
+end)
diff --git a/test/pip/yamlfix_spec.lua b/test/pip/yamlfix_spec.lua
new file mode 100644
index 0000000..1fad53e
--- /dev/null
+++ b/test/pip/yamlfix_spec.lua
@@ -0,0 +1,13 @@
+describe('yamlfix', function()
+  it('can format', function()
+    local formatted = require('test.helper').run_fmt('yamlfix', 'yaml', {
+      [[name:   John]],
+      [[age:    30]],
+    })
+    assert.are.same({
+      [[---]],
+      [[name: John]],
+      [[age: 30]],
+    }, formatted)
+  end)
+end)
diff --git a/test/formatter/yapf_spec.lua b/test/pip/yapf_spec.lua
similarity index 78%
rename from test/formatter/yapf_spec.lua
rename to test/pip/yapf_spec.lua
index a1678a4..69ff808 100644
--- a/test/formatter/yapf_spec.lua
+++ b/test/pip/yapf_spec.lua
@@ -1,9 +1,6 @@
 describe('yapf', function()
   it('can format', function()
-    local ft = require('guard.filetype')
-    ft('python'):fmt('yapf')
-
-    local formatted = require('test.formatter.helper').test_with('python', {
+    local formatted = require('test.helper').run_fmt('yapf', 'python', {
       [[def foo(n):]],
       [[    if n in         (1,2,3):]],
       [[        return n+1]],
diff --git a/test/ruby/rubocop_spec.lua b/test/ruby/rubocop_spec.lua
new file mode 100644
index 0000000..16f0df2
--- /dev/null
+++ b/test/ruby/rubocop_spec.lua
@@ -0,0 +1,68 @@
+describe('rubocop', function()
+  local tmpdir = '/tmp/rubocop-test'
+
+  setup(function()
+    vim.fn.mkdir(tmpdir, 'p')
+    vim.fn.writefile({
+      "source 'https://rubygems.org'",
+      "gem 'rubocop'",
+    }, tmpdir .. '/Gemfile')
+    vim.system({ 'bundle', 'install' }, { cwd = tmpdir }):wait()
+  end)
+
+  it('can format', function()
+    local input = {
+      [[x = {  :a=>1,:b  =>  2  }]],
+    }
+    local result = vim
+      .system({
+        'bundle',
+        'exec',
+        'rubocop',
+        '-A',
+        '-f',
+        'quiet',
+        '--stderr',
+        '--stdin',
+        'test.rb',
+      }, {
+        stdin = table.concat(input, '\n') .. '\n',
+        cwd = tmpdir,
+      })
+      :wait()
+    local output = result.stderr or ''
+    local formatted = vim.split(output, '\n', { trimempty = true })
+    assert.is_true(#formatted > 0)
+  end)
+
+  it('can lint', function()
+    local linter = require('test.helper').get_linter('rubocop')
+    local input = {
+      [[x = {  :a=>1,:b  =>  2  }]],
+    }
+    local bufnr = vim.api.nvim_create_buf(false, true)
+    local result = vim
+      .system({
+        'bundle',
+        'exec',
+        'rubocop',
+        '--format',
+        'json',
+        '--force-exclusion',
+        '--stdin',
+        'test.rb',
+      }, {
+        stdin = table.concat(input, '\n') .. '\n',
+        cwd = tmpdir,
+      })
+      :wait()
+    local output = result.stdout or ''
+    local diagnostics = linter.parse(output, bufnr)
+    assert.is_true(#diagnostics > 0)
+    for _, d in ipairs(diagnostics) do
+      assert.equal(bufnr, d.bufnr)
+      assert.is_number(d.lnum)
+      assert.is_string(d.message)
+    end
+  end)
+end)
diff --git a/test/formatter/rustfmt_nightly_spec.lua b/test/rust/rustfmt_nightly_spec.lua
similarity index 74%
rename from test/formatter/rustfmt_nightly_spec.lua
rename to test/rust/rustfmt_nightly_spec.lua
index 584c279..d37b01e 100644
--- a/test/formatter/rustfmt_nightly_spec.lua
+++ b/test/rust/rustfmt_nightly_spec.lua
@@ -1,9 +1,6 @@
 describe('rustfmt_nightly', function()
   it('can format', function()
-    local ft = require('guard.filetype')
-    ft('rust'):fmt('rustfmt_nightly')
-
-    local formatted = require('test.formatter.helper').test_with('rust', {
+    local formatted = require('test.helper').run_fmt('rustfmt_nightly', 'rust', {
       [[use std::{collections::HashMap, collections::HashSet};]],
       [[fn    main() {]],
       [[let   var:usize=1;]],
diff --git a/test/formatter/rustfmt_spec.lua b/test/rust/rustfmt_spec.lua
similarity index 65%
rename from test/formatter/rustfmt_spec.lua
rename to test/rust/rustfmt_spec.lua
index bec9e5b..6782c85 100644
--- a/test/formatter/rustfmt_spec.lua
+++ b/test/rust/rustfmt_spec.lua
@@ -1,9 +1,6 @@
 describe('rustfmt', function()
   it('can format', function()
-    local ft = require('guard.filetype')
-    ft('rust'):fmt('rustfmt')
-
-    local formatted = require('test.formatter.helper').test_with('rust', {
+    local formatted = require('test.helper').run_fmt('rustfmt', 'rust', {
       [[use std::{collections::HashMap, collections::HashSet};]],
       [[fn    main() {]],
       [[let   var:usize=1;]],
@@ -11,7 +8,7 @@ describe('rustfmt', function()
       [[}]],
     })
     assert.are.same({
-      [[use std::{collections::HashMap, collections::HashSet};]],
+      [[use std::collections::{HashMap, HashSet};]],
       [[fn main() {]],
       [[    let var: usize = 1;]],
       [[    println!("{var}");]],
diff --git a/test/setup.sh b/test/setup.sh
deleted file mode 100644
index d1db3e1..0000000
--- a/test/setup.sh
+++ /dev/null
@@ -1,62 +0,0 @@
-#! /bin/bash
-# Setup homebrew
-eval "$(/home/linuxbrew/.linuxbrew/bin/brew shellenv)"
-
-# Install packages with package managers
-luarocks install luacheck &
-
-pip -qqq install autopep8 black djhtml docformatter flake8 isort pylint yapf codespell ruff sqlfluff clang-tidy mypy &
-
-npm install -g --silent \
-    prettier @fsouza/prettierd sql-formatter shellcheck shfmt @taplo/cli @biomejs/biome &
-
-brew install \
-    hlint ormolu clang-format golines gofumpt detekt swiftformat &
-
-# Install standalone binary packages
-bin="$HOME/.local/bin"
-gh="https://github.com"
-mkdir -p $bin
-
-# alejandra
-wget -q $gh"/kamadorueda/alejandra/releases/download/4.0.0/alejandra-x86_64-unknown-linux-musl"
-mv ./alejandra-x86_64-unknown-linux-musl $bin/alejandra
-chmod +x $bin/alejandra
-
-# cbfmt
-wget -q $gh"/lukas-reineke/cbfmt/releases/download/v0.2.0/cbfmt_linux-x86_64_v0.2.0.tar.gz"
-tar -xvf cbfmt_linux-x86_64_v0.2.0.tar.gz
-mv ./cbfmt_linux-x86_64_v0.2.0/cbfmt $bin
-chmod +x $bin/cbfmt
-
-# selene
-wget -q "$gh/Kampfkarren/selene/releases/download/0.28.0/selene-0.28.0-linux.zip"
-unzip selene-0.28.0-linux.zip -d $bin
-chmod +x $bin/selene
-
-# stylua
-wget -q "$gh/JohnnyMorganz/StyLua/releases/download/v0.18.0/stylua-linux.zip"
-unzip stylua-linux.zip -d $bin
-chmod +x $bin/stylua
-
-# latexindent
-wget -q "$gh/cmhughes/latexindent.pl/releases/download/V3.22.2/latexindent-linux"
-chmod +x latexindent-linux
-mv latexindent-linux $bin/latexindent
-
-# nixfmt
-wget -q "$gh/serokell/nixfmt/releases/download/v0.5.0/nixfmt"
-chmod +x nixfmt
-mv nixfmt $bin/nixfmt
-
-# ktlint
-wget -q "$gh/pinterest/ktlint/releases/download/1.0.0/ktlint"
-chmod +x ktlint 
-mv ktlint $bin/ktlint
-
-# test setup
-export PATH="$HOME/.local/bin:$PATH"
-luarocks install vusted
-git clone "$gh/nvimdev/guard.nvim" "$HOME/guard.nvim"
-mv "$HOME/guard.nvim/lua/guard" ./lua/
-wait
diff --git a/test/swift/swift_format_spec.lua b/test/swift/swift_format_spec.lua
new file mode 100644
index 0000000..e545f65
--- /dev/null
+++ b/test/swift/swift_format_spec.lua
@@ -0,0 +1,9 @@
+describe('swift-format', function()
+  it('can format', function()
+    local formatted = require('test.helper').run_fmt('swift-format', 'swift', {
+      [[func foo(  ){let x=1;print(x)}]],
+    })
+    assert.is_true(#formatted > 0)
+    assert.is_true(formatted[1]:find('func foo') ~= nil)
+  end)
+end)