test get renderer fcn

.github/workflows/ci.yaml

@@ -21,7 +21,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: ["ubuntu-latest"]
+        os: ["ubuntu-latest", "macos-latest", "windows-latest"]
         # Bookend python versions
         python-version: ["3.9", "3.11", "3.12"]
     steps:
@@ -52,7 +52,7 @@ jobs:
           python -c "import mplotutils"
       - name: Run tests
         timeout-minutes: 5
-        run: python -u -m pytest
+        run: python -u -m pytest -vv
           --cov=mplotutils
           --cov-report=xml
           --junitxml=test-results/${{ runner.os }}-${{ matrix.python-version }}.xml

mplotutils/tests/test_get_renderer.py

@@ -0,0 +1,44 @@
+from contextlib import contextmanager
+
+import matplotlib
+import pytest
+
+from . import figure_context
+
+
+def get_renderer(f):
+
+    if hasattr(f.canvas, "get_renderer"):
+        return f.canvas.get_renderer()
+    elif hasattr(f, "_get_renderer"):
+        return f._get_renderer()
+
+    backend = matplotlib.get_backend()
+
+    raise AttributeError(
+        f"Could not find a renderer for the '{backend}' backend. Please raise an issue"
+    )
+
+
+@contextmanager
+def restore_backend():
+
+    backend = matplotlib.get_backend()
+
+    try:
+        yield
+    except Exception:
+        matplotlib.use(backend)
+
+
+@pytest.mark.parametrize("backend", matplotlib.rcsetup.all_backends)
+def test_get_renderer(backend):
+
+    with restore_backend():
+        try:
+            matplotlib.use(backend)
+        except ImportError:
+            pytest.skip(backend)
+
+        with figure_context() as f:
+            get_renderer(f)