Make ast-serialize non-optional in tests

Author: ilevkivskyi

.github/workflows/test.yml

@@ -106,20 +106,17 @@ jobs:
           os: ubuntu-24.04-arm
           toxenv: py
           tox_extra_args: "-n 4 --mypy-num-workers=4 mypy/test/testcheck.py"
-          ast_serialize: true
         - name: Parallel tests with py314-ubuntu, mypyc-compiled
           python: '3.14'
           os: ubuntu-24.04-arm
           toxenv: py
           tox_extra_args: "-n 4 --mypy-num-workers=4 mypy/test/testcheck.py"
           test_mypyc: true
-          ast_serialize: true
         - name: Parallel tests with py314-windows-64, interpreted
           python: '3.14'
           os: windows-latest
           toxenv: py
           tox_extra_args: "-n 2 --mypy-num-workers=2 mypy/test/testcheck.py -k 'incremental or modules or classes'"
-          ast_serialize: true
 
         - name: Type check our own code (py310-ubuntu)
           python: '3.10'
@@ -142,7 +139,6 @@ jobs:
     timeout-minutes: 60
     env:
       TOX_SKIP_MISSING_INTERPRETERS: False
-      VIRTUALENV_SYSTEM_SITE_PACKAGES: ${{ matrix.ast_serialize && 1 || 0 }}
       # Rich (pip) -- Disable color for windows + pytest
       FORCE_COLOR: ${{ !(startsWith(matrix.os, 'windows-') && startsWith(matrix.toxenv, 'py')) && 1 || 0 }}
       # Tox
@@ -217,11 +213,6 @@ jobs:
         pip install -r test-requirements.txt
         CC=clang MYPYC_OPT_LEVEL=0 MYPY_USE_MYPYC=1 pip install -e .
 
-    # It is an optional dependency (for now).
-    - name: Install ast-serialize
-      if: ${{ matrix.ast_serialize }}
-      run: pip install 'ast-serialize>=0.1.1,<1.0.0'
-
     - name: Setup tox environment
       run: |
         tox run -e ${{ matrix.toxenv }} --notest

test-requirements.in

@@ -13,3 +13,4 @@ pytest-cov>=2.10.0
 setuptools>=77.0.3
 tomli>=1.1.0  # needed even on py311+ so the self check passes with --python-version 3.10
 pre_commit>=3.5.0
+ast-serialize>=0.1.1,<1.0.0

test-requirements.txt

@@ -4,6 +4,8 @@
 #
 #    pip-compile --allow-unsafe --output-file=test-requirements.txt --strip-extras test-requirements.in
 #
+ast-serialize==0.1.1
+    # via -r test-requirements.in
 attrs==25.4.0
     # via -r test-requirements.in
 cfgv==3.4.0