Clean up test: module-level import, remove stale line refs, pin exception type

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: timtreis

tests/pl/test_render_shapes.py

@@ -13,7 +13,7 @@
 from shapely.geometry import MultiPolygon, Point, Polygon
 from spatialdata import SpatialData, deepcopy
 from spatialdata.models import ShapesModel, TableModel
-from spatialdata.transformations import Affine, Identity, MapAxis, Scale, Sequence, Translation
+from spatialdata.transformations import Affine, Identity, MapAxis, Scale, Sequence, Translation, set_transformation
 from spatialdata.transformations._utils import _set_transformations
 
 import spatialdata_plot  # noqa: F401
@@ -1071,12 +1071,10 @@ def test_groups_filtering_preserves_transformation(sdata_blobs: SpatialData):
     """Regression test for #420: groups filtering must not strip coordinate-system metadata.
 
     Simulates the exact sequence that ``_render_shapes`` performs —
-    ``filter_by_coordinate_system`` ➜ groups boolean-index ➜ ``reset_index`` ➜
-    re-assign to ``sdata_filt`` — then asserts that ``_prepare_transformation``
-    can still retrieve the non-global transformation with the correct scale.
+    filter_by_coordinate_system -> groups boolean-index -> reset_index ->
+    re-assign to sdata_filt -> GeoDataFrame re-wrap — then asserts that
+    ``_prepare_transformation`` can still retrieve the correct transformation.
     """
-    from spatialdata.transformations import set_transformation
-
     from spatialdata_plot.pl.utils import _prepare_transformation
 
     scale_factor = 2.5
@@ -1090,25 +1088,23 @@ def test_groups_filtering_preserves_transformation(sdata_blobs: SpatialData):
 
     sdata_filt = sdata_blobs.filter_by_coordinate_system(coordinate_system=cs, filter_tables=False)
 
-    # --- replicate the groups-filtering path from _render_shapes (lines 382-389) ---
+    # Replicate groups filtering: boolean-index -> reset_index -> re-assign
     shapes = sdata_filt.shapes["blobs_polygons"]
     keep = shapes["cluster"] == "c1"
     shapes = shapes[keep].reset_index(drop=True)
     sdata_filt["blobs_polygons"] = shapes
-    # also replicate the GeoDataFrame re-wrap that follows (line 432), which strips .attrs
+    # GeoDataFrame re-wrap strips .attrs (this is what _render_shapes does next)
     shapes = gpd.GeoDataFrame(shapes, geometry="geometry")
 
-    # The sdata_filt element must still carry the correct transformation
-    # (this is where _render_shapes reads the transform after the fix).
+    # sdata_filt's element must still carry the correct transformation
     trans, _ = _prepare_transformation(sdata_filt.shapes["blobs_polygons"], cs)
     matrix = trans.get_matrix()
     np.testing.assert_allclose(matrix[0, 0], scale_factor, err_msg="x-scale lost after groups filtering")
     np.testing.assert_allclose(matrix[1, 1], scale_factor, err_msg="y-scale lost after groups filtering")
 
-    # The GeoDataFrame re-wrap (which _render_shapes does right after) strips
-    # attrs — prove that reading the transform from *that* object would fail,
-    # demonstrating why early capture matters.
-    with pytest.raises((KeyError, AssertionError)):
+    # The GeoDataFrame re-wrap strips attrs — reading the transform from
+    # the re-wrapped object must fail, proving why early capture matters.
+    with pytest.raises(AssertionError):
         _prepare_transformation(shapes, cs)