diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
new file mode 100644
index 0000000..2656162
--- /dev/null
+++ b/.github/workflows/test.yml
@@ -0,0 +1,88 @@
+name: Test
+
+on:
+  push:
+    branches: # on all branches except `typos`
+      - "**"
+      - "!typos"
+    paths-ignore:
+      - "docs/**"
+      - "examples/**"
+      - "data/**"
+      - ".git*"
+      - "README.md"
+  pull_request:
+    branches:
+      - "**"
+  schedule: # Every Monday at 04:00 UTC
+    - cron: "0 4 * * 1"
+
+jobs:
+  caching:
+    strategy:
+      matrix:
+        python-version: ["3.12"]
+        os: [ubuntu-latest]
+      fail-fast: false
+    env:
+      FORCE_JAVASCRIPT_ACTIONS_TO_NODE24: true
+
+    defaults:
+      run:
+        shell: bash -elo pipefail {0}
+
+    name: Cache for ${{ matrix.python-version }} on ${{ matrix.os }}
+    runs-on: ${{ matrix.os }}
+    steps:
+      - uses: actions/checkout@v6
+
+      - name: Get week number
+        run: echo "WEEK=$(date +'%V')" >> $GITHUB_ENV
+
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: mamba-org/setup-micromamba@v2
+        with:
+          create-args: python=${{ matrix.python-version }}
+          environment-file: environment-dev.yml
+          cache-environment: true
+          cache-environment-key: W${{ env.WEEK }}
+
+  run-tests:
+    needs: caching
+    strategy:
+      matrix:
+        python-version: ["3.12"]
+        os: [ubuntu-latest]
+        submodule:
+          #- { name: "io", pytest_args: "tests/test_io.py" } # To do
+          - { name: "utils", pytest_args: "tests/test_utils.py" }
+          #- { name: "viz", pytest_args: "tests/test_viz.py" } # To do
+      fail-fast: false
+
+    name: ${{ matrix.submodule.name }} (${{ matrix.python-version }} on ${{ matrix.os }})
+    runs-on: ${{ matrix.os }}
+    timeout-minutes: 60
+    defaults:
+      run:
+        shell: bash -el {0}
+
+    steps:
+      - uses: actions/checkout@v6
+
+      - name: Get week number
+        run: echo "WEEK=$(date +'%V')" >> $GITHUB_ENV
+
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: mamba-org/setup-micromamba@v2
+        with:
+          create-args: python=${{ matrix.python-version }}
+          environment-file: environment-dev.yml
+          cache-environment: true
+          cache-environment-key: W${{ env.WEEK }}
+
+      - name: Install bikenetlib
+        run: pip install --no-build-isolation --no-deps -e .
+
+      - name: "Run tests ${{ matrix.submodule.name }}"
+        run: |
+          pytest ${{ matrix.submodule.pytest_args }}
diff --git a/README.md b/README.md
index fd3c9a6..a82be3f 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,10 @@
 # Bike Net Kit / Bike Net Lib
 
+[![Ruff](https://img.shields.io/endpoint?url=https://raw.githubusercontent.com/astral-sh/ruff/main/assets/badge/v2.json)](https://github.com/astral-sh/ruff)
+[![code style: prettier](https://img.shields.io/badge/code_style-prettier-ff69b4.svg?style=flat-square)](https://github.com/prettier/prettier)
+[![pre-commit](https://img.shields.io/badge/pre--commit-enabled-brightgreen?logo=pre-commit&logoColor=white)](https://github.com/pre-commit/pre-commit)
+[![Test](https://github.com/BikeNetKit/BikeNetLib/actions/workflows/test.yml/badge.svg?branch=main)](https://github.com/BikeNetKit/BikeNetLib/actions/workflows/test.yml)
+
 > [!WARNING]  
 > This repository is under heavy development and not yet functional. Do not use.
 
diff --git a/bikenetlib/utils.py b/bikenetlib/utils.py
index 3727619..90cddf5 100644
--- a/bikenetlib/utils.py
+++ b/bikenetlib/utils.py
@@ -236,58 +236,6 @@ def update_seed_points_with_existing_bike_network(seed_points_snapped, nodes_exn
     seed_points_snapped.set_index("osmid", drop=False, inplace=True)
     return seed_points_snapped
 
-def get_grid_seed_points(edges, seed_point_spacing, principal_bearing):
-    """Get grid seed points for street network, rotated by principal bearing
-
-    Adapted from: https://github.com/gboeing/osmnx-examples/blob/v0.11/notebooks/17-street-network-orientations.ipynb
-
-    Parameters
-    ----------
-    edges: geopandas.geodataframe.GeoDataFrame
-        The street network, in a projected coordinate reference system
-    seed_point_spacing: int
-        Distance between seed points, in meters
-    principal_bearing: float
-        Principal bearing (most common bearing of streets)
-
-    Returns
-    -------
-    seed_points: geopandas.geodataframe.GeoDataFrame
-        Seed points, rotated by principal bearing, to be snapped, in the same projected coordinate reference system as edges
-    """
-
-    # Rotate edges counter to the principal bearing
-    edges_temp = edges.copy()
-    edges_temp.geometry = edges_temp.geometry.rotate(principal_bearing, origin=(0, 0))
-
-    # Create grid
-    # get convex hull around edge area
-    hull = edges_temp.union_all().convex_hull
-    # get bounds of hull
-    xmin, ymin, xmax, ymax = hull.bounds
-
-    # https://stackoverflow.com/questions/66010964/fastest-way-to-produce-a-grid-of-points-that-fall-within-a-polygon-or-shape
-    # Populate hull bbox with evenly spaced seeding points
-    points = []
-    for x in np.arange(xmin, xmax, seed_point_spacing):
-        for y in np.arange(ymin, ymax, seed_point_spacing):
-            points.append(Point((round(x, 4), round(y, 4))))
-
-    # Keep only those seed points that are within the hull polygon
-    prep_polygon = prep(hull)
-    valid_points = []
-    valid_points.extend(filter(prep_polygon.contains, points))
-
-    # store seed points in gdf
-    seed_points = gpd.GeoDataFrame({"geometry": valid_points}, crs=edges.crs)
-
-    # Rotate points back using the principal bearing
-    seed_points.geometry = seed_points.geometry.rotate(
-        -1 * principal_bearing, origin=(0, 0)
-    )
-
-    return seed_points
-
 
 def get_principal_bearing(G):
     """Determine the most common (principal) bearing, for the best grid orientation.
diff --git a/tests/test_data/copenhagen.dbf b/tests/test_data/copenhagen.dbf
new file mode 100644
index 0000000..101a0ec
Binary files /dev/null and b/tests/test_data/copenhagen.dbf differ
diff --git a/tests/test_data/copenhagen.prj b/tests/test_data/copenhagen.prj
new file mode 100644
index 0000000..a30c00a
--- /dev/null
+++ b/tests/test_data/copenhagen.prj
@@ -0,0 +1 @@
+GEOGCS["GCS_WGS_1984",DATUM["D_WGS_1984",SPHEROID["WGS_1984",6378137,298.257223563]],PRIMEM["Greenwich",0],UNIT["Degree",0.017453292519943295]]
\ No newline at end of file
diff --git a/tests/test_data/copenhagen.qpj b/tests/test_data/copenhagen.qpj
new file mode 100644
index 0000000..5fbc831
--- /dev/null
+++ b/tests/test_data/copenhagen.qpj
@@ -0,0 +1 @@
+GEOGCS["WGS 84",DATUM["WGS_1984",SPHEROID["WGS 84",6378137,298.257223563,AUTHORITY["EPSG","7030"]],AUTHORITY["EPSG","6326"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.0174532925199433,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4326"]]
diff --git a/tests/test_data/copenhagen.shp b/tests/test_data/copenhagen.shp
new file mode 100644
index 0000000..81dc6e6
Binary files /dev/null and b/tests/test_data/copenhagen.shp differ
diff --git a/tests/test_data/copenhagen.shx b/tests/test_data/copenhagen.shx
new file mode 100644
index 0000000..66e4f92
Binary files /dev/null and b/tests/test_data/copenhagen.shx differ
diff --git a/tests/test_data/oelde_grid.gpkg b/tests/test_data/oelde_grid.gpkg
new file mode 100644
index 0000000..d0d867f
Binary files /dev/null and b/tests/test_data/oelde_grid.gpkg differ
diff --git a/tests/test_data/oelde_growbikenet.gpkg b/tests/test_data/oelde_growbikenet.gpkg
new file mode 100644
index 0000000..232c1a2
Binary files /dev/null and b/tests/test_data/oelde_growbikenet.gpkg differ
diff --git a/tests/test_data/oelde_streets.gpkg b/tests/test_data/oelde_streets.gpkg
new file mode 100644
index 0000000..9ed1ae4
Binary files /dev/null and b/tests/test_data/oelde_streets.gpkg differ
diff --git a/tests/test_io.py b/tests/test_io.py
new file mode 100644
index 0000000..b76dadd
--- /dev/null
+++ b/tests/test_io.py
@@ -0,0 +1,13 @@
+import pytest
+import osmnx as ox
+import pandas as pd
+import geopandas as gpd
+from pandas.testing import assert_frame_equal
+from bikenetlib.io import (
+    prepare_network,
+    download_pois,
+    save_to_file,
+)
+from shapely.geometry import Point, LineString, MultiLineString
+
+# To do
\ No newline at end of file
diff --git a/tests/test_utils.py b/tests/test_utils.py
new file mode 100644
index 0000000..de6f05f
--- /dev/null
+++ b/tests/test_utils.py
@@ -0,0 +1,88 @@
+import pytest
+import osmnx as ox
+import pandas as pd
+import geopandas as gpd
+from pandas.testing import assert_frame_equal
+from bikenetlib.utils import ( # List them in the order appearing in utils.py
+    intersects_properly,
+    get_principal_bearing,
+    filter_seed_points,
+)
+from shapely.geometry import Point, LineString, MultiLineString
+
+
+# intersects_properly
+
+@pytest.fixture
+def geom_1():
+    linestring = LineString([(0, 0), (1, 1), (2, 2)])
+    return linestring
+
+
+@pytest.fixture
+def geom_2():
+    linestring = LineString([(3, 3), (4, 4), (5, 5)])
+    return linestring
+
+
+def test_intersects_properly(geom_1, geom_2):
+    assert intersects_properly(geom_1, geom_2) is False
+
+
+# filter_seed_points
+
+@pytest.fixture
+def seed_point_delta():
+    return 500
+
+
+@pytest.fixture
+def snapped_seed_points():
+    d = {
+        "osmid": ["1", "2", "3"],
+        "geometry_generated": [Point(1000, 1000), Point(2000, 2000), Point(3000, 3000)],
+    }
+    gdf = gpd.GeoDataFrame(d, geometry="geometry_generated", crs="EPSG:3857")
+    gdf["geometry_osm"] = gpd.GeoSeries(
+        [Point(1001, 1001), Point(10000, 10000), Point(3001, 3001)], crs="EPSG:3857"
+    )
+    return gdf
+
+
+@pytest.fixture
+def filtered_seed_points():
+    d = {"osmid": ["1", "3"], "geometry": [Point(1001, 1001), Point(3001, 3001)]}
+    gdf = gpd.GeoDataFrame(d, geometry="geometry", crs="EPSG:3857")
+    gdf = gdf.set_index("osmid")
+    gdf["osmid"] = gdf.index
+    gdf = gdf.iloc[:, [1, 0]]
+    return gdf
+
+
+def test_filter_seed_points(
+    snapped_seed_points, filtered_seed_points, seed_point_delta
+):
+    assert_frame_equal(
+        filter_seed_points(snapped_seed_points, seed_point_delta),
+        filtered_seed_points,
+        check_dtype=False,
+    )
+
+
+# get_principal_bearing
+
+@pytest.fixture
+def validation_streets():
+    streets_nodes = gpd.read_file(
+        "./tests/test_data/oelde_streets.gpkg", layer="nodes"
+    ).set_index("osmid")
+    streets_edges = gpd.read_file(
+        "./tests/test_data/oelde_streets.gpkg", layer="edges"
+    ).set_index(["u", "v", "key"])
+    streets = ox.convert.graph_from_gdfs(streets_nodes, streets_edges)
+    return streets
+
+
+def test_get_principal_bearing(validation_streets):
+    assert get_principal_bearing(validation_streets) == 65.0
+
diff --git a/tests/test_viz.py b/tests/test_viz.py
new file mode 100644
index 0000000..17efb5f
--- /dev/null
+++ b/tests/test_viz.py
@@ -0,0 +1 @@
+# To do
\ No newline at end of file