test cibuildwheel wheels in Docker on Windows

.github/workflows/wheels-test.ps1

@@ -0,0 +1,22 @@
+param ([string]$venv, [string]$pillow="C:\pillow")
+$ErrorActionPreference  = 'Stop'
+$ProgressPreference = 'SilentlyContinue'
+Set-PSDebug -Trace 1
+if ("$venv" -like "*\cibw-run-*\pp*-win_amd64\*") {
+    # unlike CPython, PyPy requires Visual C++ Redistributable to be installed
+    [Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12
+    Invoke-WebRequest -Uri 'https://aka.ms/vs/15/release/vc_redist.x64.exe' -OutFile 'vc_redist.x64.exe'
+    C:\vc_redist.x64.exe /install /quiet /norestart | Out-Null
+}
+$env:path += ";$pillow\winbuild\build\bin\"
+& "$venv\Scripts\activate.ps1"
+& reg add "HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\python.exe" /v "GlobalFlag" /t REG_SZ /d "0x02000000" /f
+cd $pillow
+& python -VV
+if (!$?) { exit $LASTEXITCODE }
+& python selftest.py
+if (!$?) { exit $LASTEXITCODE }
+& python -m pytest -vx Tests\check_wheel.py
+if (!$?) { exit $LASTEXITCODE }
+& python -m pytest -vx Tests
+if (!$?) { exit $LASTEXITCODE }

.github/workflows/wheels-test.sh

@@ -1,10 +1,6 @@
 #!/bin/bash
 set -e
 
-EXP_CODECS="jpg jpg_2000 libtiff zlib"
-EXP_MODULES="freetype2 littlecms2 pil tkinter webp"
-EXP_FEATURES="fribidi harfbuzz libjpeg_turbo raqm transp_webp webp_anim webp_mux xcb"
-
 if [[ "$OSTYPE" == "darwin"* ]]; then
     brew install fribidi
     export PKG_CONFIG_PATH="/usr/local/opt/openblas/lib/pkgconfig"
@@ -25,21 +21,5 @@ fi
 
 # Runs tests
 python3 selftest.py
+python3 -m pytest Tests/check_wheel.py
 python3 -m pytest
-
-# Test against expected codecs, modules and features
-codecs=$(python3 -c 'from PIL.features import *; print(" ".join(sorted(get_supported_codecs())))')
-if [ "$codecs" != "$EXP_CODECS" ]; then
-    echo "Codecs should be: '$EXP_CODECS'; but are '$codecs'"
-    exit 1
-fi
-modules=$(python3 -c 'from PIL.features import *; print(" ".join(sorted(get_supported_modules())))')
-if [ "$modules" != "$EXP_MODULES" ]; then
-    echo "Modules should be: '$EXP_MODULES'; but are '$modules'"
-    exit 1
-fi
-features=$(python3 -c 'from PIL.features import *; print(" ".join(sorted(get_supported_features())))')
-if [ "$features" != "$EXP_FEATURES" ]; then
-    echo "Features should be: '$EXP_FEATURES'; but are '$features'"
-    exit 1
-fi

.github/workflows/wheels.yml

@@ -148,12 +148,16 @@ jobs:
         env:
           CIBW_ARCHS: ${{ matrix.cibw_arch }}
           CIBW_BEFORE_ALL: "{package}\\winbuild\\build\\build_dep_all.cmd"
+          CIBW_CACHE_PATH: "C:\\cibw"
           CIBW_TEST_SKIP: "*-win_arm64"
           CIBW_TEST_COMMAND: >-
-            reg.exe add "HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\python.exe" /v "GlobalFlag" /t REG_SZ /d "0x02000000" /f &&
-            cd /d {project} &&
-            python.exe selftest.py &&
-            python.exe -m pytest -vx -W always Tests
+            docker run --rm
+            -v {project}:C:\pillow
+            -v C:\cibw:C:\cibw
+            -v %CD%\..\venv-test:%CD%\..\venv-test
+            -e CI -e GITHUB_ACTIONS
+            mcr.microsoft.com/windows/servercore:ltsc2022
+            powershell C:\pillow\.github\workflows\wheels-test.ps1 %CD%\..\venv-test
         shell: cmd
 
       - uses: actions/upload-artifact@v3

Tests/check_wheel.py

@@ -0,0 +1,38 @@
+import importlib.util
+import sys
+
+from PIL import features
+
+
+def test_wheel_modules():
+    expected_modules = {"pil", "tkinter", "freetype2", "littlecms2", "webp"}
+
+    # tkinter is not available in cibuildwheel installed CPython on Windows
+    if not importlib.util.find_spec("tkinter"):
+        expected_modules.remove("tkinter")
+
+    assert set(features.get_supported_modules()) == expected_modules
+
+
+def test_wheel_codecs():
+    expected_codecs = {"jpg", "jpg_2000", "zlib", "libtiff"}
+
+    assert set(features.get_supported_codecs()) == expected_codecs
+
+
+def test_wheel_features():
+    expected_features = {
+        "webp_anim",
+        "webp_mux",
+        "transp_webp",
+        "raqm",
+        "fribidi",
+        "harfbuzz",
+        "libjpeg_turbo",
+        "xcb",
+    }
+
+    if sys.platform == "win32":
+        expected_features.remove("xcb")
+
+    assert set(features.get_supported_features()) == expected_features

Tests/helper.py

@@ -5,6 +5,7 @@ Helper functions.
 import logging
 import os
 import shutil
+import subprocess
 import sys
 import sysconfig
 import tempfile
@@ -258,11 +259,21 @@ def hopper(mode=None, cache={}):
 
 
 def djpeg_available():
-    return bool(shutil.which("djpeg"))
+    if shutil.which("djpeg"):
+        try:
+            subprocess.check_call(["djpeg", "-version"])
+            return True
+        except subprocess.CalledProcessError:
+            return False
 
 
 def cjpeg_available():
-    return bool(shutil.which("cjpeg"))
+    if shutil.which("cjpeg"):
+        try:
+            subprocess.check_call(["cjpeg", "-version"])
+            return True
+        except subprocess.CalledProcessError:
+            return False
 
 
 def netpbm_available():

Tests/test_imagegrab.py

@@ -15,6 +15,8 @@ class TestImageGrab:
         sys.platform not in ("win32", "darwin"), reason="requires Windows or macOS"
     )
     def test_grab(self):
+        if os.environ.get("USERNAME") == "ContainerAdministrator":
+            pytest.skip("can't grab screen when running in Docker")
         ImageGrab.grab()
         ImageGrab.grab(include_layered_windows=True)
         ImageGrab.grab(all_screens=True)

pyproject.toml

@@ -88,7 +88,7 @@ version = {attr = "PIL.__version__"}
 
 [tool.cibuildwheel]
 before-all = ".github/workflows/wheels-dependencies.sh"
-config-settings = "raqm=enable raqm=vendor fribidi=vendor"
+config-settings = "raqm=enable raqm=vendor fribidi=vendor imagequant=disable"
 test-command = "cd {project} && .github/workflows/wheels-test.sh"
 test-extras = "tests"