test: add comprehensive test suite for visualization and comparison modules

tests/test_wafer_map_item.py

@@ -0,0 +1,91 @@
+"""Tests for src/pygui/backend/visualization/wafer_map_item.py."""
+from unittest.mock import MagicMock, patch
+
+import pytest
+
+
+# Use the session-scoped qapp fixture from conftest.py so Qt Property/Signal
+# descriptors work properly.
+pytestmark = pytest.mark.usefixtures("qapp")
+
+
+def test_export_image_valid_path():
+    """export_image saves a PNG when grabToImage succeeds."""
+    from pygui.backend.visualization.wafer_map_item import WaferMapItem
+
+    item = WaferMapItem()
+
+    mock_image = MagicMock()
+    mock_result = MagicMock()
+    mock_result.image.return_value = mock_image
+    item.grabToImage = MagicMock(return_value=mock_result)
+
+    assert item.export_image("/tmp/test_wafer.png") is True
+
+
+def test_export_image_empty_path():
+    """export_image returns False for empty/None path."""
+    from pygui.backend.visualization.wafer_map_item import WaferMapItem
+
+    item = WaferMapItem()
+    assert item.export_image("") is False
+    assert item.export_image(None) is False
+
+
+def test_export_image_grab_fails():
+    """export_image returns False when grabToImage raises."""
+    from pygui.backend.visualization.wafer_map_item import WaferMapItem
+
+    item = WaferMapItem()
+    item.grabToImage = MagicMock(side_effect=RuntimeError("grab failed"))
+
+    assert item.export_image("/tmp/test_wafer.png") is False
+
+
+def test_export_image_save_fails():
+    """export_image returns False when image.save raises."""
+    from pygui.backend.visualization.wafer_map_item import WaferMapItem
+
+    mock_image = MagicMock()
+    mock_image.save.side_effect = IOError("disk full")
+    mock_result = MagicMock()
+    mock_result.image.return_value = mock_image
+
+    item = WaferMapItem()
+    item.grabToImage = MagicMock(return_value=mock_result)
+
+    assert item.export_image("/tmp/test_wafer.png") is False
+
+
+def test_thickness_properties():
+    """Thickness data properties exist with correct defaults."""
+    from pygui.backend.visualization.wafer_map_item import WaferMapItem
+
+    item = WaferMapItem()
+
+    assert item._thickness_data == []
+    assert item._show_thickness is False
+
+
+def test_thickness_setter_updates_data():
+    """Setting thicknessData updates _thickness_data."""
+    from pygui.backend.visualization.wafer_map_item import WaferMapItem
+
+    item = WaferMapItem()
+    item._rebuild_thickness = MagicMock()
+
+    item.thicknessData = [1.0, 2.0, 3.0]
+
+    assert item._thickness_data == [1.0, 2.0, 3.0]
+    assert item._rebuild_thickness.called
+
+
+def test_show_thickness_setter():
+    """Setting showThickness updates _show_thickness."""
+    from pygui.backend.visualization.wafer_map_item import WaferMapItem
+
+    item = WaferMapItem()
+    assert item._show_thickness is False
+
+    item.showThickness = True
+    assert item._show_thickness is True