Add required test suite and websocket fixes

tests/test_api_admin.py

@@ -1,2 +1,42 @@
-def test_placeholder_api_admin():
-    assert True
+from conftest import admin_login, create_quiz, create_session, join_student
+
+
+def test_admin_login_required_and_quiz_session_crud(client, sample_pool):
+    assert client.get("/admin/").status_code == 401
+    assert client.post("/admin/login", json={"password": "wrong"}).status_code == 401
+
+    admin_login(client)
+    assert client.get("/admin/").status_code == 200
+    quiz_id = create_quiz(client, sample_pool)
+    quizzes = client.get("/admin/api/quizzes").json()["quizzes"]
+    assert any(item["id"] == quiz_id for item in quizzes)
+
+    response = client.post("/admin/api/sessions", json={"quiz_id": quiz_id})
+    assert response.status_code == 200
+    payload = response.json()
+    assert len(payload["sid"]) == 6
+    assert payload["join_url"].endswith(f"?sid={payload['sid']}")
+    assert payload["qr_url"].startswith("data:image/svg+xml;base64,")
+
+    sessions = client.get("/admin/api/sessions").json()["sessions"]
+    assert sessions[0]["sid"] == payload["sid"]
+
+
+def test_quiz_upload_and_csv_export(client, sample_pool):
+    sid = create_session(client, sample_pool)
+    join_student(client, sid, "s1", "Student One")
+    csv_response = client.get(f"/admin/api/sessions/{sid}/csv")
+    assert csv_response.status_code == 200
+    assert "student_id,name,question_idx" in csv_response.text
+
+    upload = client.post(
+        "/admin/api/quizzes/upload",
+        files={"file": ("pool.json", __import__("json").dumps(sample_pool), "application/json")},
+    )
+    assert upload.status_code == 200
+
+
+def test_invalid_quiz_and_session_errors(client):
+    admin_login(client)
+    assert client.post("/admin/api/quizzes", json={"pool_json": {"title": "bad", "questions": []}}).status_code == 400
+    assert client.post("/admin/api/sessions", json={"quiz_id": 999}).status_code == 404