feat: detect double-click launch on Windows and abort with info message (#570)

---------

Co-authored-by: Jens Bergmann <1742418+1cu@users.noreply.github.com>

tests/unit/test_launch_mode_guard.py

@@ -0,0 +1,107 @@
+# SPDX-FileCopyrightText: © Jens Bergmann and contributors
+# SPDX-License-Identifier: AGPL-3.0-or-later
+# SPDX-ArtifactOfProjectHomePage: https://github.com/Second-Hand-Friends/kleinanzeigen-bot/
+
+import builtins, importlib, sys  # isort: skip
+from unittest import mock
+
+import pytest
+
+from kleinanzeigen_bot.utils.i18n import Locale
+
+
+# --- Platform-specific test for Windows double-click guard ---
+@pytest.mark.parametrize(
+    ("compiled_exe", "windows_double_click_launch", "expected_error_msg_lang"),
+    [
+        (True, True, "en"),  # Windows Explorer double-click - English locale
+        (True, True, "de"),  # Windows Explorer double-click - German locale
+        (True, False, None),  # Windows Terminal launch - compiled exe
+        (False, False, None),  # Windows Terminal launch - from source code
+    ],
+)
+@pytest.mark.skipif(sys.platform != "win32", reason = "ctypes.windll only exists on Windows")
+def test_guard_triggers_on_double_click_windows(
+    monkeypatch:pytest.MonkeyPatch,
+    capsys:pytest.CaptureFixture[str],
+    compiled_exe:bool,
+    windows_double_click_launch:bool | None,
+    expected_error_msg_lang:str | None
+) -> None:
+    # Prevent blocking in tests
+    monkeypatch.setattr(builtins, "input", lambda: None)
+
+    # Simulate target platform
+    monkeypatch.setattr(sys, "platform", "win32")
+
+    # Simulate compiled executable
+    monkeypatch.setattr(
+        "kleinanzeigen_bot.utils.misc.is_frozen",
+        lambda: compiled_exe,
+    )
+
+    # Force specific locale
+    if expected_error_msg_lang:
+        monkeypatch.setattr(
+            "kleinanzeigen_bot.utils.i18n.get_current_locale",
+            lambda: Locale(expected_error_msg_lang),
+        )
+
+    # Spy on sys.exit
+    exit_mock = mock.Mock(wraps = sys.exit)
+    monkeypatch.setattr(sys, "exit", exit_mock)
+
+    # Simulate double-click launch on Windows
+    if windows_double_click_launch is not None:
+        pid_count = 2 if windows_double_click_launch else 3  # 2 -> Explorer, 3 -> Terminal
+        k32 = mock.Mock()
+        k32.GetConsoleProcessList.return_value = pid_count
+        monkeypatch.setattr("ctypes.windll.kernel32", k32)
+
+    # Reload module to pick up system monkeypatches
+    guard = importlib.reload(
+        importlib.import_module("kleinanzeigen_bot.utils.launch_mode_guard")
+    )
+
+    if expected_error_msg_lang:
+        with pytest.raises(SystemExit) as exc:
+            guard.ensure_not_launched_from_windows_explorer()
+        assert exc.value.code == 1
+        exit_mock.assert_called_once_with(1)
+
+        captured = capsys.readouterr()
+        if expected_error_msg_lang == "de":
+            assert "Du hast das Programm scheinbar per Doppelklick gestartet." in captured.err
+        else:
+            assert "It looks like you launched it by double-clicking the EXE." in captured.err
+        assert not captured.out  # nothing to stdout
+    else:
+        guard.ensure_not_launched_from_windows_explorer()
+        exit_mock.assert_not_called()
+        captured = capsys.readouterr()
+        assert not captured.err  # nothing to stderr
+
+
+# --- Platform-agnostic tests for non-Windows and non-frozen code paths ---
+@pytest.mark.parametrize(
+    ("platform", "compiled_exe"),
+    [
+        ("linux", True),
+        ("linux", False),
+        ("darwin", True),
+        ("darwin", False),
+    ],
+)
+def test_guard_non_windows_and_non_frozen(
+    monkeypatch:pytest.MonkeyPatch,
+    platform:str,
+    compiled_exe:bool
+) -> None:
+    monkeypatch.setattr(sys, "platform", platform)
+    monkeypatch.setattr("kleinanzeigen_bot.utils.misc.is_frozen", lambda: compiled_exe)
+    # Reload module to pick up system monkeypatches
+    guard = importlib.reload(
+        importlib.import_module("kleinanzeigen_bot.utils.launch_mode_guard")
+    )
+    # Should not raise or print anything
+    guard.ensure_not_launched_from_windows_explorer()