Revamp authentication routes structure (#201)

* Fix #68: use makefun to generate dynamic dependencies

* Remove every Starlette imports

* Split every routers and remove event handlers

* Make users router optional

* Pass after_update handler to get_users_router

* Update documentation

* Remove test file

* Write migration doc for splitted routers

tests/test_router_auth.py

@@ -0,0 +1,96 @@
+from typing import cast, Dict, Any
+
+import httpx
+import pytest
+from fastapi import FastAPI, status
+
+from fastapi_users.authentication import Authenticator
+from fastapi_users.router import ErrorCode, get_auth_router
+from tests.conftest import MockAuthentication, UserDB
+
+
+@pytest.fixture
+@pytest.mark.asyncio
+async def test_app_client(
+    mock_user_db, mock_authentication, get_test_client
+) -> httpx.AsyncClient:
+    mock_authentication_bis = MockAuthentication(name="mock-bis")
+    authenticator = Authenticator(
+        [mock_authentication, mock_authentication_bis], mock_user_db
+    )
+
+    mock_auth_router = get_auth_router(mock_authentication, mock_user_db, authenticator)
+    mock_bis_auth_router = get_auth_router(
+        mock_authentication_bis, mock_user_db, authenticator
+    )
+
+    app = FastAPI()
+    app.include_router(mock_auth_router, prefix="/mock")
+    app.include_router(mock_bis_auth_router, prefix="/mock-bis")
+
+    return await get_test_client(app)
+
+
+@pytest.mark.router
+@pytest.mark.parametrize("path", ["/mock/login", "/mock-bis/login"])
+@pytest.mark.asyncio
+class TestLogin:
+    async def test_empty_body(self, path, test_app_client: httpx.AsyncClient):
+        response = await test_app_client.post(path, data={})
+        assert response.status_code == status.HTTP_422_UNPROCESSABLE_ENTITY
+
+    async def test_missing_username(self, path, test_app_client: httpx.AsyncClient):
+        data = {"password": "guinevere"}
+        response = await test_app_client.post(path, data=data)
+        assert response.status_code == status.HTTP_422_UNPROCESSABLE_ENTITY
+
+    async def test_missing_password(self, path, test_app_client: httpx.AsyncClient):
+        data = {"username": "king.arthur@camelot.bt"}
+        response = await test_app_client.post(path, data=data)
+        assert response.status_code == status.HTTP_422_UNPROCESSABLE_ENTITY
+
+    async def test_not_existing_user(self, path, test_app_client: httpx.AsyncClient):
+        data = {"username": "lancelot@camelot.bt", "password": "guinevere"}
+        response = await test_app_client.post(path, data=data)
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+        data = cast(Dict[str, Any], response.json())
+        assert data["detail"] == ErrorCode.LOGIN_BAD_CREDENTIALS
+
+    async def test_wrong_password(self, path, test_app_client: httpx.AsyncClient):
+        data = {"username": "king.arthur@camelot.bt", "password": "percival"}
+        response = await test_app_client.post(path, data=data)
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+        data = cast(Dict[str, Any], response.json())
+        assert data["detail"] == ErrorCode.LOGIN_BAD_CREDENTIALS
+
+    async def test_valid_credentials(
+        self, path, test_app_client: httpx.AsyncClient, user: UserDB
+    ):
+        data = {"username": "king.arthur@camelot.bt", "password": "guinevere"}
+        response = await test_app_client.post(path, data=data)
+        assert response.status_code == status.HTTP_200_OK
+        assert response.json() == {"token": str(user.id)}
+
+    async def test_inactive_user(self, path, test_app_client: httpx.AsyncClient):
+        data = {"username": "percival@camelot.bt", "password": "angharad"}
+        response = await test_app_client.post(path, data=data)
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+        data = cast(Dict[str, Any], response.json())
+        assert data["detail"] == ErrorCode.LOGIN_BAD_CREDENTIALS
+
+
+@pytest.mark.router
+@pytest.mark.parametrize("path", ["/mock/logout", "/mock-bis/logout"])
+@pytest.mark.asyncio
+class TestLogout:
+    async def test_missing_token(self, path, test_app_client: httpx.AsyncClient):
+        response = await test_app_client.post(path)
+        assert response.status_code == status.HTTP_401_UNAUTHORIZED
+
+    async def test_valid_credentials(
+        self, mocker, path, test_app_client: httpx.AsyncClient, user: UserDB
+    ):
+        response = await test_app_client.post(
+            path, headers={"Authorization": f"Bearer {user.id}"}
+        )
+        assert response.status_code == status.HTTP_200_OK