feat(tests): Add full test coverage for netCDF loader

Author: Sparshr04

movement/napari/loader_widgets.py

@@ -199,7 +199,10 @@ def _on_load_clicked(self):
             return
 
         # Format data for napari layers
-        self._format_data_for_layers()
+        success = self._format_data_for_layers()
+        if not success:
+            return  # Stop execution if formatting/validation failed
+
         logger.info("Converted dataset to a napari Tracks array.")
         logger.debug(f"Tracks array shape: {self.data.shape}")
         if self.data_bboxes is not None:
@@ -229,7 +232,7 @@ def _format_data_for_layers(self):
                 ds = xr.open_dataset(self.file_path)
             except Exception as e:
                 show_error(f"Error opening netCDF file: {e}")
-                return
+                return False
 
             # Get the dataset type from its attributes
             ds_type = ds.attrs.get("ds_type", None)
@@ -247,13 +250,13 @@ def _format_data_for_layers(self):
                         f"The netCDF file does not appear to be a valid "
                         f"movement {ds_type} dataset: {e}"
                     )
-                    return
+                    return False
             else:
                 show_error(
                     f"The netCDF file has an unknown 'ds_type' attribute:"
                     f"{ds_type}."
                 )
-                return
+                return False
         else:
             # Original Logic continue
             loader = (
@@ -270,6 +273,7 @@ def _format_data_for_layers(self):
 
         # Find rows that do not contain NaN values
         self.data_not_nan = ~np.any(np.isnan(self.data), axis=1)
+        return True
 
     def _set_common_color_property(self):
         """Set the color property for the Points and Tracks layers.

tests/fixtures/files.py

@@ -9,6 +9,7 @@
 
 import h5py
 import pytest
+import xarray as xr
 from sleap_io.io.slp import read_labels, write_labels
 from sleap_io.model.labels import LabeledFrame, Labels
 
@@ -499,3 +500,28 @@ def via_track_ids_not_unique_per_frame():
         '"{""name"":""rect"",""x"":2567.627,""y"":466.888,""width"":40,""height"":37}",'
         '"{""track"":""71""}"'  # same track ID as the previous row
     )
+
+
+@pytest.fixture(scope="session")
+def invalid_netcdf_file_missing_confidence(tmp_path_factory):
+    """Create an invalid 'poses' netCDF file missing the
+    'confidence' variable.
+    """
+    from pytest import DATA_PATHS
+
+    # 1. Get path to a VALID file (the 'poses' one)
+    valid_file = DATA_PATHS.get("MOVE_two-mice_octagon.analysis.nc")
+
+    # 2. Load it
+    ds = xr.open_dataset(valid_file)
+
+    # 3. Break it (our validator requires 'confidence' for 'poses')
+    del ds["confidence"]
+
+    # 4. Save to a temp file
+    temp_dir = tmp_path_factory.mktemp("invalid_netcdf")
+    invalid_path = temp_dir / "invalid_file_missing_confidence.nc"
+    ds.to_netcdf(invalid_path)
+
+    # 5. Yield the path to the test
+    yield str(invalid_path)

tests/test_unit/test_napari_plugin/test_data_loader_widget.py

@@ -398,6 +398,36 @@ def test_on_load_clicked_with_valid_file_path(
     assert expected_log_messages <= log_messages
 
 
+def test_on_load_clicked_with_invalid_netcdf(
+    make_napari_viewer_proxy,
+    mocker,
+    invalid_netcdf_file_missing_confidence,  # Our new fixture
+):
+    """Test that show_error is called when loading an invalid netCDF file."""
+    data_loader_widget = DataLoader(make_napari_viewer_proxy())
+
+    # 1. Mock the show_error function so we can check if it's called
+    mock_show_error = mocker.patch("movement.napari.loader_widgets.show_error")
+
+    # 2. Set up the widget to load the broken file
+    data_loader_widget.file_path_edit.setText(
+        invalid_netcdf_file_missing_confidence
+    )
+    data_loader_widget.source_software_combo.setCurrentText(
+        "movement (netCDF)"
+    )
+
+    # 3. Click "Load"
+    data_loader_widget._on_load_clicked()
+
+    # 4. Assert that show_error was called
+    mock_show_error.assert_called_once()
+
+    # 5. Assert the error message is correct
+    call_args = mock_show_error.call_args[0][0]  # Get the first argument
+    assert "does not appear to be a valid movement poses dataset" in call_args
+
+
 # ------------------- tests for dimension slider ----------------------------#
 # These tests check that the frame slider is set to the expected range
 @pytest.mark.parametrize(