Set up an extremely lightweight set of tests for the user infra implementation

src/infra/db_test.py

@@ -0,0 +1,8 @@
+from src.infra import Base
+from sqlalchemy import Engine, create_engine
+
+
+def mock_db() -> Engine:
+    engine = create_engine('sqlite:///:memory:', echo=True)
+    Base.metadata.create_all(engine)
+    return engine

src/infra/users_test.py

@@ -0,0 +1,31 @@
+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
+from src.infra.db_test import mock_db
+import pytest
+
+DB = mock_db()
+
+
+@pytest.fixture
+def db():
+    return DB
+
+
+@pytest.fixture
+def repo(db):
+    return UserRepoImpl(db)
+
+
+@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),
+    ]
+
+
+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