diff --git a/.eslintrc.json b/.eslintrc.json
index 5e1e09a..8aa4652 100644
--- a/.eslintrc.json
+++ b/.eslintrc.json
@@ -20,6 +20,7 @@
         "embeddedLanguageFormatting": "off"
       }
     ],
+    "eqeqeq": "error",
     "require-atomic-updates": 0,
     "no-extra-semi": 0,
     "no-mixed-spaces-and-tabs": 0,
diff --git a/.github/workflows/unittests.yml b/.github/workflows/unittests.yml
new file mode 100644
index 0000000..d086f1e
--- /dev/null
+++ b/.github/workflows/unittests.yml
@@ -0,0 +1,27 @@
+name: Unit tests
+on:
+  push:
+    branches:
+    - main
+  pull_request:
+    branches:
+    - main
+jobs:
+  build:
+    runs-on: ubuntu-22.04
+    strategy:
+      fail-fast: false
+      matrix:
+        node-version: [20.x, 22.x, 24.x]
+    steps:
+    - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
+    - name: Use Node.js ${{ matrix.node-version }}
+      uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4
+      with:
+        node-version: ${{ matrix.node-version }}
+    - name: Install plugin
+      run: npm ci
+    - name: Lint
+      run: npm run lint
+    - name: Run unit tests
+      run: npm test
diff --git a/README.md b/README.md
index f4c79e0..251e7c3 100644
--- a/README.md
+++ b/README.md
@@ -1 +1,58 @@
-# Base plugin 
\ No newline at end of file
+# @sitespeed.io/plugin
+
+Base class for [sitespeed.io](https://www.sitespeed.io/) plugins. Extend it,
+implement `processMessage`, and sitespeed.io will instantiate and drive your
+plugin through the message queue.
+
+See the [plugin documentation](https://www.sitespeed.io/documentation/sitespeed.io/plugins/#how-to-create-your-own-plugin)
+for the full plugin lifecycle.
+
+## Install
+
+```bash
+npm install @sitespeed.io/plugin
+```
+
+## Usage
+
+```js
+import { SitespeedioPlugin } from '@sitespeed.io/plugin';
+
+export default class MyPlugin extends SitespeedioPlugin {
+  constructor(options, context, queue) {
+    super({ name: 'myplugin', options, context, queue });
+  }
+
+  async open() {
+    // optional: setup on startup
+  }
+
+  async processMessage(message) {
+    if (message.type === 'url') {
+      this.log.info('Got a URL: %s', message.url);
+      await this.sendMessage('myplugin.data', { hello: 'world' });
+    }
+  }
+
+  async close() {
+    // optional: cleanup on shutdown
+  }
+}
+```
+
+## API
+
+- `this.name` / `getName()` — plugin name
+- `this.options` / `getOptions()` — sitespeed.io start options
+- `this.context` / `getContext()` — sitespeed.io context
+- `this.queue` — the message queue
+- `this.log` / `getLog()` — logger (call levels directly: `this.log.info(...)`)
+- `getStorageManager()` — storage manager for writing files
+- `getFilterRegistry()` — filter registry for TimeSeries metrics
+- `sendMessage(type, data, extras)` — post a message on the queue
+- `open()` / `close()` — lifecycle hooks (override as needed)
+- `processMessage(message)` — **must be implemented** by your subclass
+
+## License
+
+MIT
diff --git a/package-lock.json b/package-lock.json
index 87586f5..08c6bc0 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -14,6 +14,9 @@
         "eslint-plugin-prettier": "4.2.1",
         "eslint-plugin-unicorn": "45.0.2",
         "prettier": "2.8.4"
+      },
+      "engines": {
+        "node": ">=20.0.0"
       }
     },
     "node_modules/@babel/code-frame": {
@@ -239,6 +242,7 @@
       "resolved": "https://registry.npmjs.org/acorn/-/acorn-8.8.2.tgz",
       "integrity": "sha512-xjIYgE8HBrkpd/sJqOGNspf8uHG+NOHGOw6a/Urj8taM2EXfdNAH2oFcPeIFfsv3+kz/mJrS5VuMqbNLjCa2vw==",
       "dev": true,
+      "peer": true,
       "bin": {
         "acorn": "bin/acorn"
       },
@@ -489,6 +493,7 @@
       "resolved": "https://registry.npmjs.org/eslint/-/eslint-8.34.0.tgz",
       "integrity": "sha512-1Z8iFsucw+7kSqXNZVslXS8Ioa4u2KM7GPwuKtkTFAqZ/cHMcEaR+1+Br0wLlot49cNxIiZk5wp8EAbPcYZxTg==",
       "dev": true,
+      "peer": true,
       "dependencies": {
         "@eslint/eslintrc": "^1.4.1",
         "@humanwhocodes/config-array": "^0.11.8",
@@ -1335,6 +1340,7 @@
       "resolved": "https://registry.npmjs.org/prettier/-/prettier-2.8.4.tgz",
       "integrity": "sha512-vIS4Rlc2FNh0BySk3Wkd6xmwxB0FpOndW5fisM5H8hsZSxU2VWVB5CWIkIjWvrHjIhxk2g3bfMKM87zNTrZddw==",
       "dev": true,
+      "peer": true,
       "bin": {
         "prettier": "bin-prettier.js"
       },
diff --git a/package.json b/package.json
index f1a709f..7f148a2 100644
--- a/package.json
+++ b/package.json
@@ -11,7 +11,8 @@
   ],
   "scripts": {
     "lint": "eslint .",
-    "lint:fix": "eslint . --fix"
+    "lint:fix": "eslint . --fix",
+    "test": "node --test"
   },
   "keywords": [
     "sitespeed.io",
@@ -23,6 +24,9 @@
     "url": "https://github.com/sitespeedio/plugin.git"
   },
   "license": "MIT",
+  "engines": {
+    "node": ">=20.0.0"
+  },
   "devDependencies": {
     "eslint": "8.34.0",
     "eslint-config-prettier": "8.6.0",
diff --git a/plugin.js b/plugin.js
index 62392a2..19691c6 100644
--- a/plugin.js
+++ b/plugin.js
@@ -6,9 +6,14 @@
  */
 export class SitespeedioPlugin {
   constructor(config) {
-    if (this.constructor == SitespeedioPlugin) {
+    if (this.constructor === SitespeedioPlugin) {
       throw new Error("Abstract plugin can't be instantiated.");
     }
+    if (!config || !config.name || !config.context || !config.queue) {
+      throw new Error(
+        'SitespeedioPlugin requires a config object with name, context and queue'
+      );
+    }
     if (config.name.includes('.')) {
       throw new Error("sitespeed.io plugin names can't contain dots");
     }
@@ -17,18 +22,9 @@ export class SitespeedioPlugin {
     this.context = config.context;
     this.queue = config.queue;
     this.make = config.context.messageMaker(this.name).make;
-    this.log = config.context.getLogger(
-      `sitespeed.io.plugin.${config.name}`
-    );
-  }
-
-  /**
-   * Log a message. Default log level is info.
-   * @param {*} message
-   * @param {*} level - trace|verbose|debug|info|warn|error|critical
-   */
-  log(message, level = 'info', ...args) {
-    this.log[level](message, args);
+    // Logger instance. Call levels directly, e.g. this.log.info(msg).
+    // Levels: trace|verbose|debug|info|warn|error|critical
+    this.log = config.context.getLogger(`sitespeed.io.plugin.${config.name}`);
   }
 
   /**
diff --git a/test/plugin.test.js b/test/plugin.test.js
new file mode 100644
index 0000000..0b492c1
--- /dev/null
+++ b/test/plugin.test.js
@@ -0,0 +1,130 @@
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+
+import { SitespeedioPlugin } from '../plugin.js';
+
+function makeContext() {
+  return {
+    messageMaker(name) {
+      return {
+        make(type, data, extras) {
+          return { type, data, extras, source: name };
+        }
+      };
+    },
+    getLogger(channel) {
+      return { channel, info() {}, warn() {}, error() {} };
+    },
+    filterRegistry: { id: 'registry' },
+    storageManager: { id: 'storage' }
+  };
+}
+
+function makeQueue() {
+  const posted = [];
+  return {
+    posted,
+    postMessage(message) {
+      posted.push(message);
+      return message;
+    }
+  };
+}
+
+class TestPlugin extends SitespeedioPlugin {
+  async processMessage() {}
+}
+
+class NoProcessPlugin extends SitespeedioPlugin {}
+
+test('abstract base class cannot be instantiated directly', () => {
+  assert.throws(
+    () =>
+      new SitespeedioPlugin({
+        name: 'x',
+        context: makeContext(),
+        queue: makeQueue()
+      }),
+    /Abstract plugin can't be instantiated/
+  );
+});
+
+test('rejects plugin names containing a dot', () => {
+  assert.throws(
+    () =>
+      new TestPlugin({
+        name: 'bad.name',
+        context: makeContext(),
+        queue: makeQueue()
+      }),
+    /can't contain dots/
+  );
+});
+
+test('rejects config missing required fields', () => {
+  assert.throws(() => new TestPlugin(), /requires a config object/);
+  assert.throws(
+    () => new TestPlugin({ context: makeContext(), queue: makeQueue() }),
+    /requires a config object/
+  );
+  assert.throws(
+    () => new TestPlugin({ name: 'p', queue: makeQueue() }),
+    /requires a config object/
+  );
+  assert.throws(
+    () => new TestPlugin({ name: 'p', context: makeContext() }),
+    /requires a config object/
+  );
+});
+
+test('getters return the values passed in via config', () => {
+  const context = makeContext();
+  const queue = makeQueue();
+  const options = { some: 'option' };
+  const plugin = new TestPlugin({ name: 'myplugin', options, context, queue });
+
+  assert.equal(plugin.getName(), 'myplugin');
+  assert.equal(plugin.getOptions(), options);
+  assert.equal(plugin.getContext(), context);
+  assert.equal(plugin.getStorageManager(), context.storageManager);
+  assert.equal(plugin.getFilterRegistry(), context.filterRegistry);
+  assert.equal(plugin.getLog().channel, 'sitespeed.io.plugin.myplugin');
+});
+
+test('sendMessage posts a made message to the queue', async () => {
+  const context = makeContext();
+  const queue = makeQueue();
+  const plugin = new TestPlugin({ name: 'myplugin', context, queue });
+
+  await plugin.sendMessage('myplugin.data', { hello: 'world' }, { extra: 1 });
+
+  assert.equal(queue.posted.length, 1);
+  assert.deepEqual(queue.posted[0], {
+    type: 'myplugin.data',
+    data: { hello: 'world' },
+    extras: { extra: 1 },
+    source: 'myplugin'
+  });
+});
+
+test('default processMessage throws when not overridden', async () => {
+  const plugin = new NoProcessPlugin({
+    name: 'noproc',
+    context: makeContext(),
+    queue: makeQueue()
+  });
+  await assert.rejects(
+    () => plugin.processMessage({ type: 'anything' }),
+    /must be implemented/
+  );
+});
+
+test('default open and close resolve without error', async () => {
+  const plugin = new TestPlugin({
+    name: 'myplugin',
+    context: makeContext(),
+    queue: makeQueue()
+  });
+  await plugin.open();
+  await plugin.close();
+});