ci: improve matrix and change filters

This is in preparation for wider parallelization of jobs, and for better
quality matrix jobs.

.github/workflows/tests.yaml

@@ -20,8 +20,11 @@ jobs:
     permissions:
       pull-requests: read
     outputs:
+      project: ${{ steps.changes.outputs.project }}
       fixtures-pypi: ${{ steps.changes.outputs.fixtures-pypi }}
-      pytest: ${{ steps.changes.outputs.pytest }}
+      tests-mypy: ${{ steps.changes.outputs.tests-mypy }}
+      tests-pytest: ${{ steps.changes.outputs.tests-pytest }}
+      tests-pytest-export: ${{ steps.changes.outputs.tests-pytest-export }}
     steps:
       - uses: actions/checkout@v4
       - uses: dorny/paths-filter@v3
@@ -30,18 +33,38 @@ jobs:
           filters: |
             workflow: &workflow
               - '.github/workflows/tests.yaml'
-            fixtures-pypi:
-              - *workflow
-              - 'tests/repositories/fixtures/pypi.org/**'
-            pytest:
+            project: &project
               - *workflow
               - 'poetry.lock'
               - 'pyproject.toml'
+            fixtures-pypi:
+              - *workflow
+              - 'tests/repositories/fixtures/pypi.org/**'
+            tests-mypy:
+              - *project
+              - 'src/**.py'
+            tests-pytest:
+              - *project
               - 'src/**.py'
               - 'tests/**'
+            tests-pytest-export:
+              - *project
+              - 'src/**.py'
+
+  lockfile:
+    name: Check poetry.lock
+    runs-on: ubuntu-latest
+    needs: changes
+    if: needs.changes.outputs.project == 'true'
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: ./.github/actions/bootstrap-poetry
+
+      - run: poetry check --lock
 
   fixtures-pypi:
-    name: PyPI Fixtures
+    name: Check fixtures (PyPI)
     runs-on: ubuntu-latest
     needs: changes
     if: needs.changes.outputs.fixtures-pypi == 'true'
@@ -59,69 +82,66 @@ jobs:
         run: git diff --exit-code --stat HEAD tests/repositories/fixtures/pypi.org
 
   pytest:
-    name: ${{ matrix.os }} / ${{ matrix.python-version }}
-    runs-on: ${{ matrix.image }}
-    needs: changes
+    name: ${{ matrix.os.name }} / ${{ matrix.python-version }}
+    runs-on: ${{ matrix.os.image }}
+    needs:
+      - changes
+      - lockfile
     strategy:
       matrix:
-        os: [Ubuntu, macOS, Windows]
-        python-version: ["3.8", "3.9", "3.10", "3.11", "3.12"]
-        include:
-          - os: Ubuntu
+        os:
+          - name: Ubuntu
             image: ubuntu-22.04
-          - os: Windows
-            image: windows-2022
-          - os: macOS
+          - name: macOS
             image: macos-12
+          - name: Windows
+            image: windows-2022
+        python-version: ["3.8", "3.9", "3.10", "3.11", "3.12"]
       fail-fast: false
     steps:
       - uses: actions/checkout@v4
-        if: needs.changes.outputs.pytest == 'true'
+        if: needs.changes.outputs.tests-pytest == 'true'
 
       - uses: ./.github/actions/bootstrap-poetry
-        if: needs.changes.outputs.pytest == 'true'
+        if: needs.changes.outputs.tests-pytest == 'true'
         with:
           python-version: ${{ matrix.python-version }}
 
       - run: poetry install --with github-actions
-        if: needs.changes.outputs.pytest == 'true'
-
-      - name: Check lock file
-        if: needs.changes.outputs.pytest == 'true'
-        run: poetry check --lock
+        if: needs.changes.outputs.tests-pytest == 'true'
 
       - name: Run mypy
-        if: needs.changes.outputs.pytest == 'true'
+        if: needs.changes.outputs.tests-pytest == 'true'
         run: poetry run mypy
 
       - name: Run pytest
-        if: needs.changes.outputs.pytest == 'true'
+        if: needs.changes.outputs.tests-pytest == 'true'
         env:
           POETRY_TEST_INTEGRATION_GIT_USERNAME: ${{ github.actor }}
           POETRY_TEST_INTEGRATION_GIT_PASSWORD: ${{ github.token }}
         run: poetry run pytest --integration -v
 
       - name: Get Plugin Version (poetry-plugin-export)
         id: poetry-plugin-export-version
-        if: needs.changes.outputs.pytest == 'true'
+        if: needs.changes.outputs.tests-pytest == 'true'
         run: |
           echo version=$(poetry show poetry-plugin-export | grep version | cut -d : -f 2 | xargs) >> $GITHUB_OUTPUT
 
       - name: Checkout Plugin Source (poetry-plugin-export)
         uses: actions/checkout@v4
-        if: needs.changes.outputs.pytest == 'true'
+        if: needs.changes.outputs.tests-pytest == 'true'
         with:
           path: poetry-plugin-export
           repository: python-poetry/poetry-plugin-export
           ref: refs/tags/${{ steps.poetry-plugin-export-version.outputs.version }}
 
       - name: Run pytest (poetry-plugin-export)
-        if: needs.changes.outputs.pytest == 'true'
+        if: needs.changes.outputs.tests-pytest == 'true'
         working-directory: ./poetry-plugin-export
         run: poetry run -C .. pytest -v
 
       - name: Check for clean working tree
-        if: needs.changes.outputs.pytest == 'true'
+        if: needs.changes.outputs.tests-pytest == 'true'
         run: |
           git diff --exit-code --stat HEAD
           git -C poetry-plugin-export diff --exit-code --stat HEAD