diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
new file mode 100644
index 0000000..a1011af
--- /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: "Functions",
+            pytest_args: "tests/test_functions.py" }
+      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 linkbikenet
+        run: pip install --no-build-isolation --no-deps -e .
+
+      - name: "Run tests ${{ matrix.submodule.name }}"
+        run: |
+          pytest ${{ matrix.submodule.pytest_args }}
diff --git a/environment-dev.yml b/environment-dev.yml
new file mode 100644
index 0000000..abbf3dd
--- /dev/null
+++ b/environment-dev.yml
@@ -0,0 +1,32 @@
+name: lbnenvdev
+channels:
+  - conda-forge
+dependencies:
+  - python=3.12
+  - jupyter
+  - jupyterlab
+  - ipywidgets
+  - ipykernel
+  - matplotlib
+  - geopandas>=0.14
+  - osmnx>=1.9.4
+  - pip
+  - pytest
+  - pixi-pycharm
+  - pre-commit
+  - sphinx
+  - numpydoc
+  - myst-nb
+  - sphinx-book-theme
+  - nbsphinx
+  - myst-parser
+  - ipython
+  - pip:
+      # not available via conda-forge:
+      - opencv-python
+      - pre-commit
+      - sphinxcontrib-bibtex
+      - sphinx-copybutton
+      - sphinx-gallery
+      - python-slugify
+      - furo
\ No newline at end of file
diff --git a/environment.yml b/environment.yml
new file mode 100644
index 0000000..7d66d2a
--- /dev/null
+++ b/environment.yml
@@ -0,0 +1,8 @@
+name: lbnenv
+channels:
+  - conda-forge
+dependencies:
+  - python>=3.12
+  - osmnx>=2.10
+  - networkx>=3.6.1
+  - numpy>=2.4.6
\ No newline at end of file
diff --git a/pyproject.toml b/pyproject.toml
new file mode 100644
index 0000000..20fe579
--- /dev/null
+++ b/pyproject.toml
@@ -0,0 +1,59 @@
+[build-system]
+requires = ["setuptools >= 77.0.3"]
+build-backend = "setuptools.build_meta"
+
+[project]
+name = "linkbikenet"
+version = "0.5.0"
+authors = [
+  { name = "Manuel Knepper" },
+  { name = "Michael Szell" },
+]
+maintainers = [{ name = "Manuel Knepper", email = "manuel.knepper@gmx.net" }]
+license = "AGPL-3.0-or-later"
+readme = "README.md"
+description = "BikeNetKit Python package to link disconnected bicycle network components"
+keywords = ["Bicycle network planning", "Networks", "OpenStreetMap", "Urban Planning", "Urban Mobility"]
+classifiers = [
+    "Development Status :: 3 - Alpha",
+    "Intended Audience :: Developers",
+    "Intended Audience :: Science/Research",
+    "Operating System :: OS Independent",
+    "Programming Language :: Python :: 3",
+    "Programming Language :: Python :: 3 :: Only",
+    "Programming Language :: Python :: 3.10",
+    "Programming Language :: Python :: 3.11",
+    "Programming Language :: Python :: 3.12",
+    "Natural Language :: English",
+]
+requires-python = ">=3.10"
+dependencies = [
+    "geopandas>=0.14",
+    "matplotlib",
+    "osmnx>=1.9.4",
+    "geojson",
+    "pip",
+    "numpy",
+]
+
+[project.urls]
+Repository = "https://github.com/BikeNetKit/LinkBikeNet"
+Issues = "https://github.com/BikeNetKit/LinkBikeNet/issues"
+
+[project.optional-dependencies]
+test = ["pytest"]
+doc = ["sphinx", "momepy"]
+
+[tool.ruff.lint.extend-per-file-ignores]
+"__init__.py" = ["F401"]  # "Imported but unused: happens with packages
+
+[tool.setuptools.packages.find]
+exclude = [
+    "examples*",
+    "tests*",
+    "results",
+    "docs*",
+    "data*",
+    "scripts*",
+]
+namespaces = false
\ No newline at end of file
diff --git a/tests/test_functions.py b/tests/test_functions.py
new file mode 100644
index 0000000..db5fb08
--- /dev/null
+++ b/tests/test_functions.py
@@ -0,0 +1,38 @@
+import networkx as nx
+import pytest
+from linkbikenet.functions import *
+
+@pytest.fixture
+def create_test_components_largest():
+    G = nx.Graph()
+    G.add_nodes_from([(1, {"x": 1, "y": 2}), (2, {"x": 5, "y": 6}), (3, {"x": 7, "y": 8}), (4, {"x": 10, "y": 10}), (5, {"x": 11, "y": 11}), (6, {"x": 15, "y": 20})])
+    G.add_edges_from([(1, 2, {'length': 5}), (2, 3, {'length': 2}), (1, 3, {'length': 7}), (4, 5, {'length': 1})])
+    wcc = [G.subgraph(c).copy() for c in sorted(nx.connected_components(G), key=lambda c: sum(
+        [l[-1] for l in G.subgraph(c).copy().edges.data('length')]), reverse=True)]
+    return wcc
+
+@pytest.fixture
+def create_validation_pair_largest():
+    pair = 3,4
+    return pair
+
+def test_pair_between_largest_components(create_test_components_largest, create_validation_pair_largest):
+    assert pair_between_largest_components(create_test_components_largest) == create_validation_pair_largest
+
+
+@pytest.fixture
+def create_test_components_nearest():
+    G = nx.Graph()
+    G.add_nodes_from([(1, {"x": 1, "y": 2}), (2, {"x": 5, "y": 6}), (3, {"x": 7, "y": 8}), (4, {"x": 30, "y": 30}), (5, {"x": 31, "y": 31}), (6, {"x": 10, "y": 10})])
+    G.add_edges_from([(1, 2, {'length': 5}), (2, 3, {'length': 2}), (1, 3, {'length': 7}), (4, 5, {'length': 1})])
+    wcc = [G.subgraph(c).copy() for c in sorted(nx.connected_components(G), key=lambda c: sum(
+        [l[-1] for l in G.subgraph(c).copy().edges.data('length')]), reverse=True)]
+    return wcc
+
+@pytest.fixture
+def create_validation_pair_nearest():
+    pair = 3,6
+    return pair
+
+def test_pair_between_nearest_components(create_test_components_nearest, create_validation_pair_nearest):
+    assert pair_between_nearest_components(create_test_components_nearest) == create_validation_pair_nearest