MRG, MAINT: Use context manager for tests

mne/conftest.py

@@ -192,17 +192,40 @@ def backend_name(request):
 def renderer(backend_name):
     """Yield the 3D backends."""
     from mne.viz.backends.renderer import _use_test_3d_backend
+    _check_skip_backend(backend_name)
+    with _use_test_3d_backend(backend_name):
+        from mne.viz.backends import renderer
+        yield renderer
+        renderer._close_all()
+
+
+@pytest.fixture(scope="module", params=[
+    "pyvista",
+])
+def backend_name_interactive(request):
+    """Get the backend name."""
+    yield request.param
+
+
+@pytest.yield_fixture
+def renderer_interactive(backend_name_interactive):
+    """Yield the 3D backends."""
+    from mne.viz.backends.renderer import _use_test_3d_backend
+    _check_skip_backend(backend_name_interactive)
+    with _use_test_3d_backend(backend_name_interactive, interactive=True):
+        from mne.viz.backends import renderer
+        yield renderer
+        renderer._close_all()
+
+
+def _check_skip_backend(name):
     from mne.viz.backends.tests._utils import has_mayavi, has_pyvista
-    if backend_name == 'mayavi':
+    if name == 'mayavi':
         if not has_mayavi():
             pytest.skip("Test skipped, requires mayavi.")
-    elif backend_name == 'pyvista':
+    elif name == 'pyvista':
         if not has_pyvista():
             pytest.skip("Test skipped, requires pyvista.")
-    with _use_test_3d_backend(backend_name):
-        from mne.viz.backends import renderer
-        yield renderer
-        renderer._close_all()
 
 
 @pytest.fixture(scope='function', params=[testing._pytest_param()])

mne/viz/_brain/tests/test_brain.py

@@ -137,18 +137,8 @@ def test_brain_add_text(renderer):
 
 
 @testing.requires_testing_data
-def test_brain_timeviewer(renderer):
+def test_brain_timeviewer(renderer_interactive):
     """Test _TimeViewer primitives."""
-    if renderer.get_3d_backend() == "mayavi":
-        pytest.skip()  # Skip PySurfer.TimeViewer
-    elif renderer.get_3d_backend() == "pyvista":
-        # Widgets are not available offscreen
-        import pyvista
-        orig_offscreen = pyvista.OFF_SCREEN
-        pyvista.OFF_SCREEN = False
-        # Disable testing to allow interactive window
-        renderer.MNE_3D_BACKEND_TESTING = False
-
     sample_src = read_source_spaces(src_fname)
 
     # dense version
@@ -195,9 +185,6 @@ def test_brain_timeviewer(renderer):
     link_viewer.set_playback_speed(value=0.1)
     link_viewer.toggle_playback()
 
-    if renderer.get_3d_backend() == "pyvista":
-        pyvista.OFF_SCREEN = orig_offscreen
-
 
 def test_brain_colormap():
     """Test brain's colormap functions."""

mne/viz/backends/_pysurfer_mayavi.py

@@ -457,7 +457,7 @@ def _take_3d_screenshot(figure, mode='rgb', filename=None):
 
 
 @contextmanager
-def _testing_context():
+def _testing_context(interactive):
     mlab = _import_mlab()
     orig_backend = mlab.options.backend
     mlab.options.backend = 'test'

mne/viz/backends/_pyvista.py

@@ -23,6 +23,7 @@
 
 with warnings.catch_warnings():
     warnings.filterwarnings("ignore", category=DeprecationWarning)
+    import pyvista
     from pyvista import (Plotter, BackgroundPlotter, PolyData,
                          Line, close_all, UnstructuredGrid)
     from pyvista.utilities import try_callback
@@ -114,7 +115,6 @@ class _Renderer(_BaseRenderer):
 
     def __init__(self, fig=None, size=(600, 600), bgcolor='black',
                  name="PyVista Scene", show=False, shape=(1, 1)):
-        from pyvista import OFF_SCREEN
         from .renderer import MNE_3D_BACKEND_TESTING
         figure = _Figure(title=name, size=size, shape=shape,
                          background_color=bgcolor, notebook=None)
@@ -133,7 +133,7 @@ def __init__(self, fig=None, size=(600, 600), bgcolor='black',
             self.figure = fig
 
         # Enable off_screen if sphinx-gallery or testing
-        if OFF_SCREEN:
+        if pyvista.OFF_SCREEN:
             self.figure.store['off_screen'] = True
 
         with warnings.catch_warnings():
@@ -615,11 +615,17 @@ def _the_callback(widget, event):
 
 
 @contextmanager
-def _testing_context():
-    import pyvista
+def _testing_context(interactive):
+    from . import renderer
     orig_offscreen = pyvista.OFF_SCREEN
-    pyvista.OFF_SCREEN = True
+    orig_testing = renderer.MNE_3D_BACKEND_TESTING
+    if interactive:
+        pyvista.OFF_SCREEN = False
+        renderer.MNE_3D_BACKEND_TESTING = False
+    else:
+        pyvista.OFF_SCREEN = True
     try:
         yield
     finally:
         pyvista.OFF_SCREEN = orig_offscreen
+        renderer.MNE_3D_BACKEND_TESTING = orig_testing

mne/viz/backends/renderer.py

@@ -159,20 +159,22 @@ def use_3d_backend(backend_name):
 
 
 @contextmanager
-def _use_test_3d_backend(backend_name):
+def _use_test_3d_backend(backend_name, interactive=False):
     """Create a testing viz context.
 
     Parameters
     ----------
     backend_name : str
         The 3d backend to use in the context.
+    interactive : bool
+        If True, ensure interactive elements are accessible.
     """
     global MNE_3D_BACKEND_TESTING
     orig_testing = MNE_3D_BACKEND_TESTING
     MNE_3D_BACKEND_TESTING = True
     try:
         with use_3d_backend(backend_name):
-            with _testing_context():  # noqa: F821
+            with _testing_context(interactive):  # noqa: F821
                 yield
     finally:
         MNE_3D_BACKEND_TESTING = orig_testing

mne/viz/tests/test_3d.py

@@ -668,17 +668,8 @@ def test_mixed_sources_plot_surface():
 
 @testing.requires_testing_data
 @traits_test
-def test_link_brains(renderer):
+def test_link_brains(renderer_interactive):
     """Test plotting linked brains."""
-    if renderer.get_3d_backend() == "mayavi":
-        pytest.skip()  # Skip PySurfer.TimeViewer
-    elif renderer.get_3d_backend() == "pyvista":
-        # Widgets are not available offscreen
-        import pyvista
-        orig_offscreen = pyvista.OFF_SCREEN
-        pyvista.OFF_SCREEN = False
-        # Disable testing to allow interactive window
-        renderer.MNE_3D_BACKEND_TESTING = False
     with pytest.raises(ValueError, match='is empty'):
         link_brains([])
     with pytest.raises(TypeError, match='type is Brain'):
@@ -704,8 +695,5 @@ def test_link_brains(renderer):
     )
     link_brains(brain)
 
-    if renderer.get_3d_backend() == "pyvista":
-        pyvista.OFF_SCREEN = orig_offscreen
-
 
 run_tests_if_main()