Add a CRUD Repo test helper to handle basic crud repo testing

src/infra/db_tests.py

@@ -0,0 +1,56 @@
+from sqlalchemy import Engine
+from typing import Callable
+from src.infra import CRUDRepo, Base
+import pytest
+
+
+class CRUDRepoHelper[A: Base, B, C]:
+    @pytest.fixture
+    def repo(self, db: Engine) -> CRUDRepo[A, B, C]:
+        import pdb
+
+        pdb.set_trace()
+        raise NotImplementedError()
+
+    @pytest.fixture
+    def dto(self) -> C:
+        raise NotImplementedError()
+
+    @pytest.fixture
+    def item(self, repo: CRUDRepo[A, B, C], dto: C) -> B:
+        return repo.create(dto, None)
+
+    @pytest.fixture
+    def transform(self) -> Callable[[B], B]:
+        raise NotImplementedError
+
+    @pytest.fixture
+    def expected_transformed_value(self, item: B) -> B:
+        raise NotImplementedError()
+
+    def test_create(self, item: B):
+        assert item is not None
+
+    def test_create_returns_none_if_invalid(self, repo: CRUDRepo[A, B, C], dto: C):
+        def always_invalid(*_args, **_kw):
+            raise ValueError('test')
+
+        with pytest.raises(ValueError):
+            repo.create(dto, always_invalid)
+
+    def test_create_returns_a_value_if_valid(self, repo: CRUDRepo[A, B, C], dto: C):
+        assert repo.create(dto, lambda _: None) is not None
+
+    def test_get_returns_none_when_missing(self, repo: CRUDRepo[A, B, C]):
+        assert repo.get(42) is None
+
+    def test_get_returns_a_value_if_it_exists(self, repo: CRUDRepo[A, B, C], item: B):
+        assert repo.get(1) == item
+
+    def test_update(self, repo: CRUDRepo[A, B, C], transform: Callable[[B], B], item: B, expected_transformed_value: B):
+        assert repo.update(1, transform) == expected_transformed_value
+
+    def test_delete(self, repo: CRUDRepo[A, B, C], item: B):
+        assert repo.get(1) is not None
+        repo.delete(1, None)
+        assert repo.get(1) is None