qt: Add tests for machinery

tests/unit/test_qt_machinery.py

@@ -0,0 +1,171 @@
+# vim: ft=python fileencoding=utf-8 sts=4 sw=4 et:
+
+# Copyright 2021 Florian Bruhin (The Compiler) <mail@qutebrowser.org>
+#
+# This file is part of qutebrowser.
+#
+# qutebrowser is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# qutebrowser is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with qutebrowser.  If not, see <https://www.gnu.org/licenses/>.
+
+"""Test qutebrowser.qt.machinery."""
+
+import sys
+import argparse
+import typing
+from typing import Any, Optional
+
+import pytest
+
+from qutebrowser.qt import machinery
+
+
+def test_unavailable_is_importerror():
+    with pytest.raises(ImportError):
+        raise machinery.Unavailable()
+
+
+@pytest.fixture
+def modules():
+    """Return a dict of modules to import-patch, all unavailable by default."""
+    return dict.fromkeys(machinery.WRAPPERS, False)
+
+
+def test_autoselect_none_available(
+    stubs: Any,
+    modules: dict[str, bool],
+    monkeypatch: pytest.MonkeyPatch,
+):
+    stubs.ImportFake(modules, monkeypatch).patch()
+
+    message = "No Qt wrapper found, tried PyQt6, PyQt5"
+    with pytest.raises(machinery.Error, match=message):
+        machinery._autoselect_wrapper()
+
+
+@pytest.mark.parametrize(
+    "available, expected",
+    [
+        (["PyQt6"], "PyQt6"),
+        (["PyQt5"], "PyQt5"),
+        (["PyQt5", "PyQt6"], "PyQt6"),
+    ],
+)
+def test_autoselect(
+    stubs: Any,
+    modules: dict[str, bool],
+    available: list[str],
+    expected: str,
+    monkeypatch: pytest.MonkeyPatch,
+):
+    for wrapper in available:
+        modules[wrapper] = True
+    stubs.ImportFake(modules, monkeypatch).patch()
+    assert machinery._autoselect_wrapper() == expected
+
+
+@pytest.mark.parametrize(
+    "args, env, expected",
+    [
+        # Defaults with no overrides
+        (None, None, "PyQt5"),
+        (argparse.Namespace(qt_wrapper=None), None, "PyQt5"),
+        # Only argument given
+        (argparse.Namespace(qt_wrapper="PyQt6"), None, "PyQt6"),
+        (argparse.Namespace(qt_wrapper="PyQt5"), None, "PyQt5"),
+        # Only environment variable given
+        (None, "PyQt6", "PyQt6"),
+        (None, "PyQt5", "PyQt5"),
+        # Both given
+        (argparse.Namespace(qt_wrapper="PyQt5"), "PyQt6", "PyQt5"),
+        (argparse.Namespace(qt_wrapper="PyQt6"), "PyQt5", "PyQt6"),
+        (argparse.Namespace(qt_wrapper="PyQt6"), "PyQt6", "PyQt6"),
+    ],
+)
+def test_select_wrapper(
+    args: Optional[argparse.Namespace],
+    env: Optional[str],
+    expected: str,
+    monkeypatch: pytest.MonkeyPatch,
+):
+    if env is None:
+        monkeypatch.delenv("QUTE_QT_WRAPPER", raising=False)
+    else:
+        monkeypatch.setenv("QUTE_QT_WRAPPER", env)
+
+    assert machinery._select_wrapper(args) == expected
+
+
+def test_init_multiple_implicit(monkeypatch: pytest.MonkeyPatch):
+    monkeypatch.setattr(machinery, "_initialized", True)
+    machinery.init()
+    machinery.init()
+
+
+def test_init_multiple_explicit(monkeypatch: pytest.MonkeyPatch):
+    monkeypatch.setattr(machinery, "_initialized", True)
+    machinery.init()
+
+    with pytest.raises(
+        machinery.Error, match=r"init\(\) already called before application init"
+    ):
+        machinery.init(args=argparse.Namespace(qt_wrapper="PyQt6"))
+
+
+def test_init_after_qt_import(monkeypatch: pytest.MonkeyPatch):
+    monkeypatch.setattr(machinery, "_initialized", False)
+    with pytest.raises(machinery.Error, match="Py.* already imported"):
+        machinery.init()
+
+
+@pytest.mark.parametrize(
+    "selected_wrapper, true_vars",
+    [
+        ("PyQt6", ["USE_PYQT6", "IS_QT6", "IS_PYQT"]),
+        ("PyQt5", ["USE_PYQT5", "IS_QT5", "IS_PYQT"]),
+        ("PySide6", ["USE_PYSIDE6", "IS_QT6", "IS_PYSIDE"]),
+    ],
+)
+def test_init_properly(
+    monkeypatch: pytest.MonkeyPatch, selected_wrapper: str, true_vars: str
+):
+    for wrapper in machinery.WRAPPERS:
+        monkeypatch.delitem(sys.modules, wrapper, raising=False)
+
+    monkeypatch.setattr(machinery, "_initialized", False)
+
+    bool_vars = [
+        "USE_PYQT5",
+        "USE_PYQT6",
+        "USE_PYSIDE6",
+        "IS_QT5",
+        "IS_QT6",
+        "IS_PYQT",
+        "IS_PYSIDE",
+    ]
+    # Make sure we didn't forget anything that's declared in the module.
+    # Not sure if this is a good idea. Might remove it in the future if it breaks.
+    assert set(typing.get_type_hints(machinery).keys()) == set(bool_vars) | {"WRAPPER"}
+
+    for var in ["WRAPPER"] + bool_vars:
+        monkeypatch.delattr(machinery, var)
+
+    monkeypatch.setattr(machinery, "_select_wrapper", lambda args: selected_wrapper)
+
+    machinery.init()
+    assert machinery.WRAPPER == selected_wrapper
+
+    expected_vars = dict.fromkeys(bool_vars, False)
+    expected_vars.update(dict.fromkeys(true_vars, True))
+    actual_vars = {var: getattr(machinery, var) for var in bool_vars}
+
+    assert expected_vars == actual_vars