feat: add session CSAT rating endpoint with tests

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/tests/test_ratings.py

@@ -0,0 +1,89 @@
+import pytest
+from httpx import AsyncClient
+
+pytestmark = pytest.mark.asyncio
+
+
+@pytest.fixture
+async def test_session(client: AsyncClient, auth_headers: dict, test_tree: dict):
+    """Create a test session from the test tree."""
+    response = await client.post(
+        "/api/v1/sessions",
+        json={"tree_id": test_tree["id"]},
+        headers=auth_headers,
+    )
+    assert response.status_code == 201, f"Failed to create session: {response.text}"
+    return response.json()
+
+
+@pytest.fixture
+async def completed_session(client: AsyncClient, auth_headers: dict, test_session: dict):
+    """Complete a session so it can be rated."""
+    response = await client.post(
+        f"/api/v1/sessions/{test_session['id']}/complete",
+        json={"outcome": "resolved", "outcome_notes": "Test resolved"},
+        headers=auth_headers,
+    )
+    assert response.status_code == 200, f"Failed to complete session: {response.text}"
+    return response.json()
+
+
+async def test_rate_session_success(client: AsyncClient, auth_headers: dict, completed_session: dict):
+    """Rate a completed session with CSAT score."""
+    response = await client.post(
+        f"/api/v1/sessions/{completed_session['id']}/rate",
+        json={"rating": 4, "comment": "Very helpful flow"},
+        headers=auth_headers,
+    )
+    assert response.status_code == 201
+    data = response.json()
+    assert data["rating"] == 4
+    assert data["comment"] == "Very helpful flow"
+
+
+async def test_rate_session_no_comment(client: AsyncClient, auth_headers: dict, completed_session: dict):
+    """Rate without a comment."""
+    response = await client.post(
+        f"/api/v1/sessions/{completed_session['id']}/rate",
+        json={"rating": 5},
+        headers=auth_headers,
+    )
+    assert response.status_code == 201
+    data = response.json()
+    assert data["rating"] == 5
+    assert data["comment"] is None
+
+
+async def test_rate_session_duplicate(client: AsyncClient, auth_headers: dict, completed_session: dict):
+    """Cannot rate same session twice."""
+    await client.post(
+        f"/api/v1/sessions/{completed_session['id']}/rate",
+        json={"rating": 4},
+        headers=auth_headers,
+    )
+    response = await client.post(
+        f"/api/v1/sessions/{completed_session['id']}/rate",
+        json={"rating": 5},
+        headers=auth_headers,
+    )
+    assert response.status_code == 409
+
+
+async def test_rate_session_invalid_rating(client: AsyncClient, auth_headers: dict, completed_session: dict):
+    """Rating must be 1-5."""
+    response = await client.post(
+        f"/api/v1/sessions/{completed_session['id']}/rate",
+        json={"rating": 6},
+        headers=auth_headers,
+    )
+    assert response.status_code == 422
+
+
+async def test_rate_incomplete_session(client: AsyncClient, auth_headers: dict, test_session: dict):
+    """Cannot rate a session that hasn't been completed."""
+    response = await client.post(
+        f"/api/v1/sessions/{test_session['id']}/rate",
+        json={"rating": 4},
+        headers=auth_headers,
+    )
+    assert response.status_code == 400