Test an installation without the pins of requirements.txt

Every test job installed requirements.txt before the package, and its
pins hid the versions that install_requires resolves to, so CI could not
see that pip installed 1.6.0 with numpy 2.5 and MeshPy 2026.1, with
which 13 tests fail. One more job, Python 3.12 on Ubuntu, now skips
requirements.txt and installs the package alone, as pip install
microstructpy does. It does not upload coverage, which the pinned job
of the same Python and system already reports.

The changelog also corrects its note on Python 3.13 and later: numpy
below 2 has no wheels there, but pip builds it from source. On Python
3.14 that takes under a minute, and all the tests pass.

Suggested by Kip Hart in the review of PR #120.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: rimoli

.github/workflows/python_package.yaml

@@ -4,14 +4,22 @@ on: [push]
 
 jobs:
   pytest:
-    name: pytest for py${{ matrix.python-version }} on ${{ matrix.os }}
+    name: pytest for py${{ matrix.python-version }} on ${{ matrix.os }}${{ matrix.unpinned && ', unpinned' || '' }}
 
     runs-on: ${{ matrix.os }}
     strategy:
       fail-fast: false
       matrix:
         python-version: [3.9, '3.10', '3.11', '3.12']
         os: ['ubuntu-latest', 'macos-latest', 'windows-latest']
+        unpinned: [false]
+        include:
+          # One job installs the package without the pins of
+          # requirements.txt, as pip install microstructpy does, so that the
+          # tests see the dependency versions that users get.
+          - python-version: '3.12'
+            os: 'ubuntu-latest'
+            unpinned: true
 
     steps:
     - uses: actions/checkout@main
@@ -33,6 +41,7 @@ jobs:
         pip install setuptools wheel
         pip install flake8 pytest pytest-cov coveralls
     - name: Install package requirements
+      if: ${{ !matrix.unpinned }}
       run: pip install -r requirements.txt
     - name: Install package
       run: pip install -e .
@@ -47,6 +56,7 @@ jobs:
       run: pytest --cov=src tests/
 
     - name: Coveralls
+      if: ${{ !matrix.unpinned }}
       env:
         COVERALLS_REPO_TOKEN: ${{ secrets.COVERALLS_REPO_TOKEN }}
         COVERALLS_FLAG_NAME: py${{ matrix.python-version }} on ${{ matrix.os }}

CHANGELOG.rst

@@ -15,8 +15,14 @@ Fixed
   the text files of the meshes cannot be read back, since numpy writes
   integers as ``np.int64(4)``, and ``tangent_sphere`` fails. With MeshPy
   2026, TetGen no longer keeps the elements of 3D meshes under
-  ``max_volume``. numpy below 2 has no releases for Python 3.13 and later,
-  which MicroStructPy does not support yet.
+  ``max_volume``. numpy below 2 has no wheels for Python 3.13 and later, so
+  pip builds it from source there, which needs a compiler.
+
+Changed
+'''''''
+- The continuous integration also runs the tests on an installation without
+  the pins of ``requirements.txt``, as ``pip install microstructpy`` does, so
+  that it sees the dependency versions that users get.
 
 `1.6.0`_ - 2026-10-18
 --------------------------