Fix SnapshotTool annotation test hanging on its snapshot dialog

Since the fix of #58, SnapshotTool defers its action with a zero-delay
timer. In test_annotation_tools, this action ran during the
processEvents() call of guidata's exec_dialog, before the automatic
closing of dialogs was scheduled, so the modal ResizeDialog opened by
save_snapshot was never closed and the test hung. The test only passed
under PyQt5 on Linux when run after another test, whose pending closing
timer closed the dialog; it hung when run on its own, on Windows, and
with PyQt6 or PySide6.

In unattended mode, replace the snapshot action by a recorder, run the
deferred actions within the test, and check that the action was called
once with the plot and an oriented rectangle.

Assisted-by: Claude Opus 5.5

Author: PierreRaybaut

doc/release_notes/release_2.12.md

@@ -24,3 +24,7 @@
 ⚙️ Dependencies:
 
 * Python 3.10 or later is now required, and wheels are no longer built for Python 3.9. Python 3.9 users must keep an earlier compatible release (PlotPy 2.11.x) (closes [Issue #74](https://github.com/PlotPyStack/PlotPy/issues/74))
+
+🔧 Other changes:
+
+* **Test suite** — The `SnapshotTool` annotation test no longer hangs when run on its own, on Windows or with Qt 6: it waited indefinitely for the snapshot dialog to be closed

plotpy/tests/unit/test_annotation_tools.py

@@ -5,6 +5,7 @@
 import numpy as np
 import pytest
 from guidata.qthelpers import exec_dialog, execenv, qt_app_context
+from qtpy import QtWidgets as QW
 
 from plotpy.interfaces.items import IBasePlotItem, IShapeItemType
 from plotpy.tests import vistools as ptv
@@ -97,13 +98,29 @@ def _test_annotation_tools(tool_classes: tuple[type[InteractiveTool], ...]):
         for tool_class in tool_classes:
             tool = win.manager.get_tool(tool_class)
             assert tool is not None
+            snapshot_calls: list[tuple] | None = None
+            if execenv.unattended and isinstance(tool, SnapshotTool):
+                # The snapshot action opens modal dialogs (destination size, options,
+                # file name) which are never closed in unattended mode
+                snapshot_calls = []
+                tool.action_func = lambda *args, calls=snapshot_calls: calls.append(
+                    args
+                )
             tool.activate()
             x_path = np.linspace(0, 0.5, 100)
             y_path = np.linspace(0, 0.5, 100)
             with execenv.context(accept_dialogs=True):
                 drag_mouse(win, x_path, y_path)
+            # Run the actions deferred by a zero-delay timer (e.g. the snapshot
+            # action) within this test rather than in a later event loop
+            QW.QApplication.processEvents()
             if hasattr(tool_class, "SWITCH_TO_DEFAULT_TOOL"):
                 assert win.manager.get_default_tool() == default_tool
+            if snapshot_calls is not None:
+                assert len(snapshot_calls) == 1
+                snap_plot, p0, p1 = snapshot_calls[0]
+                assert snap_plot is plot
+                assert p0.x() < p1.x() and p0.y() < p1.y()
         plot.unselect_all()
         shape_items: list[IBasePlotItem] = plot.get_items(item_type=IShapeItemType)
         plot.select_some_items(shape_items)