Merge pull request #2055 from jakevdp/saver-test

TST: use fixture to detect altair_saver

altair/examples/tests/test_examples.py

@@ -7,15 +7,14 @@
 from altair import examples
 
 
-def require_altair_saver(func):
+@pytest.fixture
+def require_altair_saver_png():
     try:
         import altair_saver  # noqa: F401
     except ImportError:
-        return pytest.mark.skip("altair_saver not importable; cannot run saver tests")(
-            func
-        )
-    else:   
-        return func
+        pytest.skip("altair_saver not importable; cannot run saver tests")
+    if "png" not in altair_saver.available_formats('vega-lite'):
+        pytest.skip("altair_saver not configured to save to png")
 
 
 def iter_example_filenames():
@@ -26,7 +25,7 @@ def iter_example_filenames():
 
 
 @pytest.mark.parametrize('filename', iter_example_filenames())
-def test_examples(filename):
+def test_examples(filename: str):
     source = pkgutil.get_data(examples.__name__, filename)
     chart = eval_block(source)
 
@@ -36,9 +35,8 @@ def test_examples(filename):
     chart.to_dict()
 
 
-@require_altair_saver
 @pytest.mark.parametrize('filename', iter_example_filenames())
-def test_render_examples_to_png(filename):
+def test_render_examples_to_png(require_altair_saver_png, filename):
     source = pkgutil.get_data(examples.__name__, filename)
     chart = eval_block(source)
     out = io.BytesIO()

altair/utils/tests/test_mimebundle.py

@@ -4,15 +4,12 @@
 from ..mimebundle import spec_to_mimebundle
 
 
-def require_altair_saver(func):
+@pytest.fixture
+def require_altair_saver():
     try:
         import altair_saver  # noqa: F401
     except ImportError:
-        return pytest.mark.skip("altair_saver not importable; cannot run saver tests")(
-            func
-        )
-    else:
-        return func
+        pytest.skip("altair_saver not importable; cannot run saver tests")
 
 
 @pytest.fixture
@@ -156,8 +153,7 @@ def vega_spec():
     }
 
 
-@require_altair_saver
-def test_vegalite_to_vega_mimebundle(vegalite_spec, vega_spec):
+def test_vegalite_to_vega_mimebundle(require_altair_saver, vegalite_spec, vega_spec):
     bundle = spec_to_mimebundle(
         spec=vegalite_spec,
         format="vega",