ci: split dev from extra

.github/workflows/extremes.yml

@@ -48,7 +48,6 @@ jobs:
       matrix:
         python-version: ["3.8"]
         os: [ubuntu-latest]
-
     runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v4
@@ -87,7 +86,6 @@ jobs:
       matrix:
         python-version: ["3.9"]
         os: [ubuntu-latest]
-
     runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v4
@@ -117,7 +115,6 @@ jobs:
           echo "$DEPS" | grep 'scipy==1.8.0'
           echo "$DEPS" | grep 'scikit-learn==1.3.0'
           echo "$DEPS" | grep 'dask==2024.7'
-
       - name: Run pytest
         run: pytest tests --cov=narwhals --cov=tests --cov-fail-under=50 --runslow
 

.github/workflows/pytest.yml

@@ -11,7 +11,6 @@ jobs:
       matrix:
         python-version: ["3.8"]
         os: [windows-latest, ubuntu-latest]
-
     runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v4
@@ -25,6 +24,7 @@ jobs:
           cache-suffix: ${{ matrix.python-version }}
           cache-dependency-glob: "pyproject.toml"
       - name: install-reqs
+        # Python3.8 is technically at end-of-life, so we don't test everything
         run: uv pip install -e ".[dev]" --system
       - name: show-deps
         run: uv pip freeze
@@ -36,7 +36,6 @@ jobs:
       matrix:
         python-version: ["3.10", "3.12"]
         os: [windows-latest]
-
     runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v4
@@ -50,22 +49,17 @@ jobs:
           cache-suffix: ${{ matrix.python-version }}
           cache-dependency-glob: "pyproject.toml"
       - name: install-reqs
-        run: uv pip install -e ".[dev]" --system
-      - name: install-dask
-        run: uv pip install --upgrade dask[dataframe] --system
-      - name: install-modin
-        run: uv pip install --upgrade modin --system
+        run: uv pip install -e ".[dev, extra]" --system
       - name: show-deps
         run: uv pip freeze
       - name: Run pytest
         run: pytest tests --cov=narwhals --cov=tests --runslow --cov-fail-under=95
 
-  pytest-coverage:
+  pytest-full-coverage:
     strategy:
       matrix:
         python-version: ["3.9", "3.11", "3.13"]
         os: [ubuntu-latest]
-
     runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v4
@@ -79,9 +73,7 @@ jobs:
           cache-suffix: ${{ matrix.python-version }}
           cache-dependency-glob: "pyproject.toml"
       - name: install-reqs
-        run: uv pip install -e ".[dev]" --system
-      - name: install-modin
-        run: uv pip install --upgrade modin[dask] --system
+        run: uv pip install -e ".[dev, extra]" --system
       - name: show-deps
         run: uv pip freeze
       - name: install ibis
@@ -92,5 +84,6 @@ jobs:
       - name: Run pytest
         run: pytest tests --cov=narwhals --cov=tests --cov-fail-under=100 --runslow
       - name: Run doctests
+        # reprs differ between versions, so we only run doctests on the latest Python
         if: matrix.python-version == '3.13'
         run: pytest narwhals --doctest-modules

CONTRIBUTING.md

@@ -96,7 +96,8 @@ Here's how you can set up your local development environment to contribute.
       uv venv -p 3.12 --seed
       ```
    4. Activate it. On Linux, this is `. .venv/bin/activate`, on Windows `.\.venv\Scripts\activate`.
-2. Install Narwhals: `uv pip install -e ".[dev, docs]"`
+2. Install Narwhals: `uv pip install -e ".[dev, docs]"`. If you also want to test Dask , PySpark, and
+   Modin, you can install them too with `uv pip install -e ".[dev, docs, extra]"`.
 3. Install a fork of griffe:
    ```
    uv pip install git+https://github.com/MarcoGorelli/griffe.git@no-overloads

pyproject.toml

@@ -34,17 +34,19 @@ dev = [
   "duckdb",
   "pandas",
   "polars",
+  "pre-commit",
   "pyarrow",
-  "pyspark; python_version >= '3.9' and python_version < '3.12'",
   "pyarrow-stubs",
   "pytest",
   "pytest-cov",
   "pytest-randomly",
   "pytest-env",
-  "hypothesis",
   "hypothesis[numpy]",
-  "scikit-learn",
   "typing_extensions",
+]
+extra = [  # heavier dependencies we don't necessarily need in every testing job
+  "scikit-learn",
+  "pyspark; python_version >= '3.9' and python_version < '3.12'",
   "dask[dataframe]; python_version >= '3.9'",
 ]
 docs = [
@@ -175,22 +177,18 @@ env = [
 plugins = ["covdefaults"]
 
 [tool.coverage.report]
+fail_under = 80  # This is just for local development, in CI we set it to 100
 omit = [
   'narwhals/typing.py',
   'narwhals/stable/v1/typing.py',
   'narwhals/this.py',
-  # we can't run this in every environment that we measure coverage on due to upper-bound constraits
-  'narwhals/_ibis/*',
-  # the latest pyspark (3.5) doesn't officially support Python 3.12 and 3.13
-  'narwhals/_spark_like/*',
+  # we don't run these in every environment
   'tests/spark_like_test.py',
 ]
 exclude_also = [
   "if sys.version_info() <",
-  "if (:?self._)?implementation is Implementation.MODIN",
   "if .*implementation is Implementation.CUDF",
   'request.applymarker\(pytest.mark.xfail',
-  '\w+._backend_version < ',
   'backend_version <',
   'if "cudf" in str\(constructor'
 ]