Enable example screenshot tests again (#350)

* Enable example screenshot tests again

* Use default lavapipe

.github/workflows/ci.yml

@@ -112,8 +112,6 @@ jobs:
     - name: Install llvmpipe and lavapipe for offscreen canvas
       run: |
         sudo apt-get update -y -qq
-        sudo add-apt-repository ppa:oibaf/graphics-drivers -y
-        sudo apt-get update
         sudo apt install -y libegl1-mesa libgl1-mesa-dri libxcb-xfixes0-dev mesa-vulkan-drivers
     - name: Install dev dependencies
       run: |
@@ -122,6 +120,8 @@ jobs:
           python download-wgpu-native.py
           pip install -e .
     - name: Test examples
+      env:
+        EXPECT_LAVAPIPE: true
       run: |
           pytest -v examples
 
@@ -184,8 +184,6 @@ jobs:
       if: matrix.os == 'ubuntu-latest'
       run: |
         sudo apt-get update -y -qq
-        sudo add-apt-repository ppa:oibaf/graphics-drivers -y
-        sudo apt-get update
         sudo apt install -y libegl1-mesa libgl1-mesa-dri libxcb-xfixes0-dev mesa-vulkan-drivers
     - name: Install dev dependencies
       run: |

examples/tests/test_examples.py

@@ -15,6 +15,7 @@
 
 from testutils import (
     can_use_wgpu_lib,
+    wgpu_backend,
     is_lavapipe,
     find_examples,
     ROOT,
@@ -63,6 +64,12 @@ def mock_time():
         yield
 
 
+def test_that_we_are_on_lavapipe():
+    print(wgpu_backend)
+    if os.getenv("EXPECT_LAVAPIPE"):
+        assert is_lavapipe
+
+
 @pytest.mark.parametrize("module", examples_to_test)
 def test_examples_screenshots(
     module, pytestconfig, force_offscreen, mock_time, request

tests/testutils.py

@@ -98,11 +98,11 @@ def _determine_can_use_glfw():
         return True
 
 
-def wgpu_backend_endswith(query):
+def get_wgpu_backend():
     """
     Query the configured wgpu backend driver.
     """
-    code = "import wgpu.utils; d = wgpu.utils.get_default_device(); print(d.adapter.properties['adapterType'], d.adapter.properties['backendType'])"
+    code = "import wgpu.utils; info = wgpu.utils.get_default_device().adapter.request_adapter_info(); print(info['adapter_type'], info['backend_type'])"
     result = subprocess.run(
         [
             sys.executable,
@@ -114,10 +114,9 @@ def wgpu_backend_endswith(query):
         universal_newlines=True,
         cwd=ROOT,
     )
-    return (
-        result.stdout.strip().endswith(query)
-        and "traceback" not in result.stderr.lower()
-    )
+    out = result.stdout.strip()
+    err = result.stderr.strip()
+    return err if "traceback" in err.lower() else out
 
 
 def find_examples(query=None, negative_query=None, return_stems=False):
@@ -139,4 +138,5 @@ def find_examples(query=None, negative_query=None, return_stems=False):
 can_use_wgpu_lib = _determine_can_use_wgpu_lib()
 can_use_glfw = _determine_can_use_glfw()
 is_ci = bool(os.getenv("CI", None))
-is_lavapipe = wgpu_backend_endswith("CPU Vulkan")
+wgpu_backend = get_wgpu_backend()
+is_lavapipe = wgpu_backend.lower() == "cpu vulkan"