[quality] test: add unit tests for screenshot_steps.py behave wrappers

tests/unit/test_screenshot_steps.py

@@ -0,0 +1,91 @@
+"""Unit tests for tests/shared/screenshot_steps.py.
+
+screenshot_steps.py registers two behave @step handlers that wrap
+take_screenshot / take_app_screenshot and assert the returned path is
+not None.  These tests verify both the happy path and the assertion
+failure path without requiring a live display or VM.
+"""
+
+import sys
+import types
+from unittest.mock import MagicMock, patch
+
+import pytest
+
+
+# ---------------------------------------------------------------------------
+# Import helper: stub out behave before importing the module under test
+# ---------------------------------------------------------------------------
+
+def _import_screenshot_steps():
+    """Import screenshot_steps with behave.step replaced by a no-op decorator."""
+    behave_stub = types.ModuleType("behave")
+    behave_stub.step = lambda *_args, **_kwargs: (lambda f: f)
+    sys.modules.setdefault("behave", behave_stub)
+
+    # Clear cached module so the stub is picked up on re-import.
+    for key in list(sys.modules):
+        if "screenshot_steps" in key and "test_" not in key:
+            del sys.modules[key]
+
+    import tests.shared.screenshot_steps as m  # noqa: PLC0415
+    return m
+
+
+_mod = _import_screenshot_steps()
+
+
+# ---------------------------------------------------------------------------
+# Helpers
+# ---------------------------------------------------------------------------
+
+def _ctx():
+    return MagicMock()
+
+
+# ---------------------------------------------------------------------------
+# step_take_screenshot_labeled
+# ---------------------------------------------------------------------------
+
+def test_take_screenshot_labeled_success():
+    """Step succeeds when take_screenshot returns a path."""
+    with patch.object(_mod, "take_screenshot", return_value="/tmp/shot.png"):
+        _mod.step_take_screenshot_labeled(_ctx(), "my-label")
+
+
+def test_take_screenshot_labeled_passes_label():
+    """Step forwards the label argument to take_screenshot."""
+    with patch.object(_mod, "take_screenshot", return_value="/tmp/shot.png") as mock_ts:
+        _mod.step_take_screenshot_labeled(_ctx(), "smoke")
+        mock_ts.assert_called_once_with("smoke")
+
+
+def test_take_screenshot_labeled_raises_on_none():
+    """Step raises AssertionError when take_screenshot returns None."""
+    with patch.object(_mod, "take_screenshot", return_value=None):
+        with pytest.raises(AssertionError, match="Screenshot failed for label 'fail-label'"):
+            _mod.step_take_screenshot_labeled(_ctx(), "fail-label")
+
+
+# ---------------------------------------------------------------------------
+# step_launch_and_screenshot
+# ---------------------------------------------------------------------------
+
+def test_launch_and_screenshot_success():
+    """Step succeeds when take_app_screenshot returns a path."""
+    with patch.object(_mod, "take_app_screenshot", return_value="/tmp/app.png"):
+        _mod.step_launch_and_screenshot(_ctx(), "org.gnome.Calculator")
+
+
+def test_launch_and_screenshot_passes_app_id():
+    """Step forwards the app_id argument to take_app_screenshot."""
+    with patch.object(_mod, "take_app_screenshot", return_value="/tmp/app.png") as mock_tas:
+        _mod.step_launch_and_screenshot(_ctx(), "org.gnome.Clocks")
+        mock_tas.assert_called_once_with("org.gnome.Clocks")
+
+
+def test_launch_and_screenshot_raises_on_none():
+    """Step raises AssertionError when take_app_screenshot returns None."""
+    with patch.object(_mod, "take_app_screenshot", return_value=None):
+        with pytest.raises(AssertionError, match="Screenshot failed for app 'org.gnome.BadApp'"):
+            _mod.step_launch_and_screenshot(_ctx(), "org.gnome.BadApp")