Use headless viewers in layer and save widget unit tests

tests/fixtures/napari.py

@@ -4,13 +4,20 @@
 import numpy as np
 import pandas as pd
 import pytest
+from napari.components import ViewerModel
 from napari.layers.base import ActionType
 
 from movement.io import save_poses
 from movement.napari.layer_wiring import on_points_data_changed
 from movement.napari.loader_widgets import POINTS_LAYER_KEY, DataLoader
 
 
+@pytest.fixture
+def headless_napari_viewer():
+    """Return a headless napari viewer model."""
+    return ViewerModel()
+
+
 @pytest.fixture
 def valid_poses_path_and_ds(valid_poses_dataset, tmp_path):
     """Return a (path, dataset) pair representing a poses dataset

tests/test_unit/test_napari_plugin/test_layer_styles.py

@@ -346,11 +346,9 @@ def test_regions_style_colors(color, expected_rgb):
 
 
 @pytest.mark.parametrize("n_shapes", [1, 3])
-def test_regions_style_set_color_all_shapes(
-    make_napari_viewer_proxy, n_shapes
-):
+def test_regions_style_set_color_all_shapes(headless_napari_viewer, n_shapes):
     """Test that set_color_all_shapes applies colors to all shapes."""
-    viewer = make_napari_viewer_proxy()
+    viewer = headless_napari_viewer
 
     # Create shapes data (rectangles)
     shapes_data = [
@@ -380,10 +378,10 @@ def test_regions_style_set_color_all_shapes(
 
 
 def test_regions_style_set_color_all_shapes_empty_layer(
-    make_napari_viewer_proxy,
+    headless_napari_viewer,
 ):
     """Test that set_color_all_shapes handles empty layers gracefully."""
-    viewer = make_napari_viewer_proxy()
+    viewer = headless_napari_viewer
     layer = viewer.add_shapes()
     # Assert it's an empty layer
     assert len(layer.data) == 0
@@ -404,12 +402,12 @@ def test_regions_style_set_color_all_shapes_empty_layer(
     ],
 )
 def test_regions_style_set_style_for_new_shapes(
-    make_napari_viewer_proxy, selected_data
+    headless_napari_viewer, selected_data
 ):
     """Test that set_style_for_new_shapes runs without error,
     regardless of whether the layer is selected or not.
     """
-    viewer = make_napari_viewer_proxy()
+    viewer = headless_napari_viewer
 
     # Create a shape
     shapes_data = [[[0, 0], [0, 10], [10, 10], [10, 0]]]

tests/test_unit/test_napari_plugin/test_layer_wiring.py

@@ -11,7 +11,6 @@
 
 import numpy as np
 import pytest
-from napari.components import ViewerModel
 from napari.components.dims import RangeTuple
 from napari.layers.base import ActionType
 
@@ -24,16 +23,6 @@
 from movement.napari.meta_widget import MovementMetaWidget
 
 
-@pytest.fixture
-def headless_napari_viewer():
-    """Return a headless napari viewer model.
-
-    Faster than make_napari_viewer_proxy because it does not
-    require Qt viewer construction and teardown.
-    """
-    return ViewerModel()
-
-
 @pytest.fixture
 def orphan_viewer_and_layers(valid_poses_path_and_ds, loaded_data_loader):
     """Return viewer and layers of a loaded dataset whose widget is gc-ed."""
@@ -211,11 +200,11 @@ def test_layer_wiring_survives_closing_metawidget(
 
 
 def test_connect_viewer_callbacks_twice_does_not_duplicate(
-    make_napari_viewer_proxy,
+    headless_napari_viewer,
 ):
     """Test that wiring a viewer twice does not duplicate the callbacks."""
     # Wire the viewer callbacks once
-    viewer = make_napari_viewer_proxy()
+    viewer = headless_napari_viewer
     connect_viewer_callbacks(viewer)
 
     # Count callbacks linked to the viewer, for each of the four events

tests/test_unit/test_napari_plugin/test_save_widget.py

@@ -18,23 +18,28 @@
 )
 
 
-def test_data_saver_widget_instantiation(make_napari_viewer_proxy):
-    """Test that the save widget is properly instantiated."""
-    data_saver_widget = DataSaver(make_napari_viewer_proxy())
+@pytest.fixture
+def data_saver_widget(headless_napari_viewer, qtbot):
+    """Return a real Qt save widget without constructing a viewer window."""
+    widget = DataSaver(headless_napari_viewer)
+    qtbot.addWidget(widget)
+    return widget
+
 
+def test_data_saver_widget_instantiation(data_saver_widget):
+    """Test that the save widget is properly instantiated."""
     assert data_saver_widget.layout().rowCount() == 1
     assert isinstance(data_saver_widget.save_button, QPushButton)
     assert data_saver_widget.save_button.objectName() == "save_button"
     assert not data_saver_widget.save_button.isEnabled()
     assert data_saver_widget.save_button.toolTip() == DISABLED_TOOLTIP
 
 
-def test_save_button_enabled_for_valid_points_layer(make_napari_viewer_proxy):
+def test_save_button_enabled_for_valid_points_layer(data_saver_widget):
     """Test that selecting a valid movement points layer enables the save
     button and updates its tooltip.
     """
-    viewer = make_napari_viewer_proxy()
-    data_saver_widget = DataSaver(viewer)
+    viewer = data_saver_widget.viewer
 
     layer = viewer.add_points(
         name="points",
@@ -70,35 +75,31 @@ def test_save_button_enabled_for_valid_points_layer(make_napari_viewer_proxy):
         ),
     ],
 )
-def test_save_button_disabled_for_invalid_layer(
-    make_layer, make_napari_viewer_proxy
-):
+def test_save_button_disabled_for_invalid_layer(make_layer, data_saver_widget):
     """Test that selecting a layer that is not a movement points layer
     keeps the save button disabled with the default tooltip.
 
     The ``points_with_properties_but_no_layer_key`` case guards against
     treating the mere presence of ``POINTS_PROPERTIES_KEY`` (even if
     falsy/None) as a stand-in for "this layer was created by movement".
     """
-    viewer = make_napari_viewer_proxy()
-    data_saver_widget = DataSaver(viewer)
+    viewer = data_saver_widget.viewer
 
     viewer.layers.selection.active = make_layer(viewer)
 
     assert not data_saver_widget.save_button.isEnabled()
     assert data_saver_widget.save_button.toolTip() == DISABLED_TOOLTIP
 
 
-def test_disabled_button_click_does_not_save(make_napari_viewer_proxy, mocker):
+def test_disabled_button_click_does_not_save(data_saver_widget, mocker):
     """Test that clicking the disabled save button (no valid layer
     selected) never opens the file dialog.
 
     This guards the invariant that the button's enabled state is the
     sole gate on saving, so ``_on_save_clicked`` can safely assume the
     active layer is a valid movement points layer.
     """
-    viewer = make_napari_viewer_proxy()
-    data_saver_widget = DataSaver(viewer)
+    viewer = data_saver_widget.viewer
 
     viewer.layers.selection.active = viewer.add_image(
         np.zeros((10, 10)), name="an image"
@@ -114,10 +115,9 @@ def test_disabled_button_click_does_not_save(make_napari_viewer_proxy, mocker):
     mock_file_dialog.assert_not_called()
 
 
-def test_save_clicked_cancelled_dialog(make_napari_viewer_proxy, mocker):
+def test_save_clicked_cancelled_dialog(data_saver_widget, mocker):
     """Test that cancelling the file dialog does not attempt to save."""
-    viewer = make_napari_viewer_proxy()
-    data_saver_widget = DataSaver(viewer)
+    viewer = data_saver_widget.viewer
 
     layer = viewer.add_points(
         name="points",
@@ -212,12 +212,11 @@ def test_save_failure_shows_error(
     assert not out_path.exists()
 
 
-def test_close_event_disconnects_selection_signal(make_napari_viewer_proxy):
+def test_close_event_disconnects_selection_signal(data_saver_widget):
     """Test that closing the widget disconnects the layer selection
     callback, so it no longer reacts to further selection changes.
     """
-    viewer = make_napari_viewer_proxy()
-    data_saver_widget = DataSaver(viewer)
+    viewer = data_saver_widget.viewer
 
     data_saver_widget.closeEvent(QCloseEvent())