test: pilot core database stub helper (#3685)

tests/test_db_stubs_helper.py

@@ -0,0 +1,121 @@
+import sys
+from contextlib import contextmanager
+from types import ModuleType
+from unittest.mock import MagicMock
+
+from pytest import MonkeyPatch
+
+from tests.helpers.db_stubs import make_core_db_stub
+
+
+_MISSING = object()
+_MODULE_NAMES = ("core", "core.database")
+
+
+@contextmanager
+def _preserve_core_modules():
+    original_modules = {
+        name: sys.modules.get(name, _MISSING) for name in _MODULE_NAMES
+    }
+    try:
+        yield
+    finally:
+        for name in _MODULE_NAMES:
+            sys.modules.pop(name, None)
+        for name, module in original_modules.items():
+            if module is not _MISSING:
+                sys.modules[name] = module
+
+
+def test_models_create_mock_attributes(monkeypatch):
+    db = make_core_db_stub(monkeypatch, models=("User", "Session"))
+
+    assert sys.modules["core.database"] is db
+    assert isinstance(db.SessionLocal, MagicMock)
+    assert isinstance(db.User, MagicMock)
+    assert isinstance(db.Session, MagicMock)
+
+
+def test_attributes_override_defaults_and_model_mocks(monkeypatch):
+    session_local = object()
+    email_account = object()
+
+    db = make_core_db_stub(
+        monkeypatch,
+        models=("EmailAccount",),
+        attributes={
+            "SessionLocal": session_local,
+            "EmailAccount": email_account,
+        },
+    )
+
+    assert db.SessionLocal is session_local
+    assert db.EmailAccount is email_account
+
+
+def test_core_module_installation_is_opt_in():
+    with _preserve_core_modules():
+        sys.modules.pop("core", None)
+        sys.modules.pop("core.database", None)
+        monkeypatch = MonkeyPatch()
+        try:
+            db = make_core_db_stub(monkeypatch)
+
+            assert "core" not in sys.modules
+            assert sys.modules["core.database"] is db
+        finally:
+            monkeypatch.undo()
+
+
+def test_existing_core_is_preserved_when_installation_is_disabled():
+    with _preserve_core_modules():
+        original_core = ModuleType("core")
+        sys.modules["core"] = original_core
+        sys.modules.pop("core.database", None)
+        monkeypatch = MonkeyPatch()
+        try:
+            db = make_core_db_stub(monkeypatch, install_core_package=False)
+
+            assert sys.modules["core"] is original_core
+            assert sys.modules["core.database"] is db
+        finally:
+            monkeypatch.undo()
+
+        assert sys.modules["core"] is original_core
+        assert "core.database" not in sys.modules
+
+
+def test_undo_removes_modules_that_were_absent():
+    with _preserve_core_modules():
+        sys.modules.pop("core", None)
+        sys.modules.pop("core.database", None)
+        monkeypatch = MonkeyPatch()
+        try:
+            make_core_db_stub(monkeypatch, install_core_package=True)
+
+            assert "core" in sys.modules
+            assert "core.database" in sys.modules
+        finally:
+            monkeypatch.undo()
+
+        assert "core" not in sys.modules
+        assert "core.database" not in sys.modules
+
+
+def test_undo_restores_existing_modules():
+    with _preserve_core_modules():
+        original_core = ModuleType("core")
+        original_database = ModuleType("core.database")
+        sys.modules["core"] = original_core
+        sys.modules["core.database"] = original_database
+        monkeypatch = MonkeyPatch()
+        try:
+            make_core_db_stub(monkeypatch, install_core_package=True)
+
+            assert sys.modules["core"] is not original_core
+            assert sys.modules["core.database"] is not original_database
+        finally:
+            monkeypatch.undo()
+
+        assert sys.modules["core"] is original_core
+        assert sys.modules["core.database"] is original_database