GH-3: Add IT for logout

tests/integration/test_auth.py

@@ -0,0 +1,35 @@
+from typing import Any, Mapping
+
+import pytest
+from flask import session
+from flask.testing import FlaskClient
+
+
+@pytest.fixture(name="config")
+def config_fixture(config: Mapping[str, Any]) -> Mapping[str, Any]:
+    return config | {"GOVUK_END_SESSION_ENDPOINT": "https://example.com/logout"}
+
+
+def test_logout_logs_out_from_oidc(client: FlaskClient) -> None:
+    with client.session_transaction() as setup_session:
+        setup_session["user"] = "test"
+        setup_session["id_token"] = "id_token"
+
+    response = client.get("/auth/logout")
+
+    assert (
+        response.status_code == 302
+        and response.location
+        == "https://example.com/logout?id_token_hint=id_token&post_logout_redirect_uri=http%3A%2F%2Flocalhost%2F"
+    )
+
+
+def test_logout_logs_out_from_schemes(client: FlaskClient) -> None:
+    with client.session_transaction() as setup_session:
+        setup_session["user"] = "test"
+        setup_session["id_token"] = "test"
+
+    with client:
+        client.get("/auth/logout")
+
+        assert "user" not in session and "id_token" not in session