From 0d884e583670f7349cd6060a86ac4f9cb568966d Mon Sep 17 00:00:00 2001
From: Campbell Alden <campbellsalden@gmail.com>
Date: Fri, 4 Sep 2026 00:08:01 +0900
Subject: [PATCH] Add a CRUD Repo test helper to handle basic crud repo testing

---
 src/infra/db_tests.py   | 56 +++++++++++++++++++++++++++++++++++++++++
 src/infra/users_test.py | 50 ++++++++++++++++++++----------------
 2 files changed, 85 insertions(+), 21 deletions(-)
 create mode 100644 src/infra/db_tests.py

diff --git a/src/infra/db_tests.py b/src/infra/db_tests.py
new file mode 100644
index 0000000..e764924
--- /dev/null
+++ b/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
diff --git a/src/infra/users_test.py b/src/infra/users_test.py
index 80ce6bc..3184b25 100644
--- a/src/infra/users_test.py
+++ b/src/infra/users_test.py
@@ -1,36 +1,44 @@
+from typing import Callable
+from sqlalchemy import Engine
+from src.infra.db_tests import CRUDRepoHelper
 from src.utils.secret import SecretBox
 from src.services.users.data import UserDTO, User
-from src.services.users.repo import UserRepo
 from src.infra.users import UserRepoImpl
 
 import pytest
 
 
-@pytest.fixture
-def repo(db):
-    return UserRepoImpl(db)
+class TestUserRepoImpl(CRUDRepoHelper):
+    @pytest.fixture
+    def repo(self, db: Engine) -> UserRepoImpl:
+        return UserRepoImpl(db)
 
+    @pytest.fixture
+    def dto(self) -> UserDTO:
+        return UserDTO('example@example.com', SecretBox('hunter1'))
 
-@pytest.fixture
-def users(repo: UserRepo):
-    return [
-        repo.create(UserDTO('example@example.com', SecretBox('hunter1')), None),
-        repo.create(UserDTO('example2@example.com', SecretBox('hunter2')), None),
-    ]
+    @pytest.fixture
+    def expected_transformed_value(self, item: User) -> User:
+        return User(id=item.id, email='example2@example.com', email_confirmed=True, password_hash=item.password_hash)
 
+    @pytest.fixture
+    def transform(self) -> Callable[[User], User]:
+        def do_transform(user: User) -> User:
+            user.email = 'example2@example.com'
+            user.email_confirmed = True
+            return user
 
-def test_getting_a_user_by_email(users: list[User], repo: UserRepo):
-    assert repo.get_user_by_email('example@example.com') == users[0]
-    assert repo.get_user_by_email('fred@example.com') is None
+        return do_transform
 
+    def test_getting_a_user_by_email(self, repo: UserRepoImpl, item: User):
+        assert repo.get_user_by_email('example@example.com') == item
+        assert repo.get_user_by_email('fred@example.com') is None
 
-def test_authenticating_as_a_user_can_succeed(users: list[User], repo: UserRepo):
-    assert repo.auth_as_user(UserDTO('example@example.com', SecretBox('hunter1'))) == users[0]
+    def test_authenticating_as_a_user_can_succeed(self, repo: UserRepoImpl, item: User):
+        assert repo.auth_as_user(UserDTO('example@example.com', SecretBox('hunter1'))) == item
 
+    def test_authenticating_fails_with_bad_password(self, repo: UserRepoImpl, item: User):
+        assert repo.auth_as_user(UserDTO('example@example.com', SecretBox('something-wrong'))) is None
 
-def test_authenticating_fails_with_bad_password(users: list[User], repo: UserRepo):
-    assert repo.auth_as_user(UserDTO('example@example.com', SecretBox('something-wrong'))) is None
-
-
-def test_authenticating_fails_for_nonexistent_user(users: list[User], repo: UserRepo):
-    assert repo.auth_as_user(UserDTO('rando@example.com', SecretBox('test123'))) is None
+    def test_authenticating_fails_for_nonexistent_user(self, repo: UserRepoImpl):
+        assert repo.auth_as_user(UserDTO('rando@example.com', SecretBox('test123'))) is None