Also run unit tests without wgpu

.github/workflows/ci.yml

@@ -92,6 +92,39 @@ jobs:
       run: |
         pytest -v tests
 
+  test-without-wgpu:
+    name: ${{ matrix.name }} without wgpu
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - name: Test py313
+            os: ubuntu-latest
+            pyversion: '3.13'
+    steps:
+    - uses: actions/checkout@v4
+    - name: Set up Python ${{ matrix.pyversion }}
+      uses: actions/setup-python@v5
+      with:
+        python-version: ${{ matrix.pyversion }}
+    - name: Install package and dev dependencies
+      run: |
+        python -m pip install --upgrade pip
+        pip install .[tests]
+        pip uninstall -y wgpu
+        rm -r rendercanvas
+    - name: Unit tests
+      run: |
+        python -c "
+        try:
+            import wgpu
+            raise RuntimeError('wgpu could be imported, but this is the no-wgpu test build')
+        except ImportError:
+            print('wgpu is (intentionally) not available')
+        "
+        pytest -v tests
+
   test-examples-build:
     name: Test examples ${{ matrix.pyversion }}
     runs-on: ${{ matrix.os }}

tests/test_context.py

@@ -1,12 +1,15 @@
 import numpy as np
-from rendercanvas.utils.bitmappresentadapter import BitmapPresentAdapter
-from rendercanvas.utils.bitmaprenderingcontext import BitmapRenderingContext
-from rendercanvas.offscreen import OffscreenRenderCanvas as ManualOffscreenRenderCanvas
-
 from testutils import can_use_wgpu_lib, run_tests
 import pytest
 
 
+from rendercanvas.offscreen import OffscreenRenderCanvas as ManualOffscreenRenderCanvas
+from rendercanvas.utils.bitmaprenderingcontext import BitmapRenderingContext
+
+if can_use_wgpu_lib:
+    from rendercanvas.utils.bitmappresentadapter import BitmapPresentAdapter
+
+
 def get_test_bitmap(width, height):
     colors = [
         (255, 0, 0, 255),

tests/test_meta.py

@@ -77,6 +77,7 @@ def test_namespace():
 def test_deps_plain_import():
     modules = get_loaded_modules("rendercanvas", 1)
     assert modules == {"rendercanvas", "sniffio"}
+    # Note, no wgpu
 
 
 @pytest.mark.skipif(sys.version_info < (3, 10), reason="Need py310+")

tests/testutils.py

@@ -5,8 +5,6 @@
 import subprocess
 from io import StringIO
 
-import wgpu
-
 
 class LogCaptureHandler(logging.StreamHandler):
     _ANSI_ESCAPE_SEQ = re.compile(r"\x1b\[[\d;]+m")
@@ -62,6 +60,10 @@ def run_tests(scope):
 
 def get_default_adapter_summary():
     """Get description of adapter, or None when no adapter is available."""
+    try:
+        import wgpu
+    except ImportError:
+        return None  # wgpu not installed
     try:
         adapter = wgpu.gpu.request_adapter_sync()
     except RuntimeError: