Use correct version of chromium for Bokeh image tests (#243)

.github/workflows/test.yml

@@ -65,6 +65,11 @@ jobs:
   test:
     name: "${{ matrix.name }} ${{ matrix.python-version }} ${{ matrix.os }}"
     runs-on: ${{ matrix.os }}
+    env:
+      # Required version of chromium used for Bokeh image tests.
+      CHROME_VER: "110.0.5481.100"
+      CHROME_REV: "chromium_2333"
+
     strategy:
       fail-fast: false
       matrix:
@@ -122,6 +127,28 @@ jobs:
           sudo apt update -yy
           sudo apt install -yy lcov
 
+      - name: Install chromium for Bokeh tests
+        if: matrix.test-text
+        run: |
+          if [[ "$(chromium --version | cut -d' ' -f2)" = "$CHROME_VER" ]]; then
+            echo "Using pre-installed version of chromium"
+          else
+            URL=https://github.com/bokeh/chromium/raw/main/linux/$CHROME_VER
+            wget --no-verbose $URL/$CHROME_REV.assert
+            wget --no-verbose $URL/$CHROME_REV.snap
+            ls -l $CHROME_REV.*
+            sudo snap ack $CHROME_REV.assert
+            sudo snap install $CHROME_REV.snap
+            snap list chromium
+            snap info chromium
+          fi
+          # Creating symlink here isn't ideal :)
+          cd /snap/bin && sudo ln -s chromium.chromedriver chromedriver
+          which chromium
+          chromium --version
+          which chromedriver
+          chromedriver --version
+
       - name: Build and install numpy from sdist
         if: matrix.build-numpy
         run: |
@@ -173,9 +200,7 @@ jobs:
           elif [[ "${{ matrix.test-text }}" != "" ]]
           then
             echo "Run normal and text tests with coverage"
-            chromium --version
-            #python -m pytest -v --color=yes tests/ --runtext --cov=lib --cov-report=lcov
-            python -m pytest -v --color=yes tests/ --cov=lib --cov-report=lcov
+            python -m pytest -v --color=yes -rP tests/test_renderer.py --runtext --cov=lib --cov-report=lcov
           elif [[ "${{ matrix.test-no-images }}" != "" ]]
           then
             echo "Run only tests that do not generate images"

pyproject.toml

@@ -42,9 +42,8 @@ docs = [
 ]
 bokeh = [
     # Optional dependencies to support use of bokeh renderer.
-    # Also needs chrome/chromium for export to PNG/SVG/buffer.
+    # Also needs chrome/chromium and chromedriver for export to PNG/SVG/buffer.
     "bokeh",
-    "chromedriver",
     "selenium",
 ]
 mypy = [

tests/test_renderer.py

@@ -7,6 +7,22 @@
 from contourpy.util.data import random
 
 
+def test_chrome_version() -> None:
+    # Print version of chrome used for export to PNG by Bokeh as test images, particularly those
+    # containing text, are sensitive to chrome version.
+    try:
+        import contourpy.util.bokeh_renderer  # noqa: F401
+    except ImportError:
+        pytest.skip("Optional bokeh dependencies not installed")
+
+    from bokeh.io.webdriver import webdriver_control
+    driver = webdriver_control.get()
+    capabilities = driver.capabilities
+    print("chrome version used by Bokeh:", capabilities["browserVersion"])
+    if "chrome" in capabilities:
+        print("chromedriver version used by Bokeh:", capabilities["chrome"]["chromedriverVersion"])
+
+
 @pytest.mark.image
 @pytest.mark.text
 @pytest.mark.parametrize("show_text", [False, True])
@@ -99,4 +115,7 @@ def test_renderer_lines(show_text: bool, line_type: LineType, renderer_type: str
 
     image_buffer = renderer.save_to_buffer()
     suffix = "" if show_text else "_no_text"
-    compare_images(image_buffer, f"renderer_lines_{renderer_type}{suffix}.png", f"{line_type}")
+    compare_images(
+        image_buffer, f"renderer_lines_{renderer_type}{suffix}.png", f"{line_type}",
+        mean_threshold=0.03 if renderer_type == "bokeh" else None,
+    )