Test with FastApi TestClient return 422 Unprocessable Entity

Question

I'm trying to run the following test with TestClient FastAPI on following endpoint.

I'm getting 422 Unprocessable Entity

def test_nodes():
    """
    this test assumes a specific id scheme, which is subject to change
    """
    response = client.get("/graphs/0/nodes?id=n:0,n:1,n:2,n:3")
    assert response.status_code == 200

@app.get("/graphs/{tree_id}/nodes")
async def get_nodes(tree_id: str, ids: str):
    server_tree = get_server_tree(tree_id)

    ids = ids.split(",")
    logging.info(ids)
    return server_tree.get_nodes(ids, short=False)

I'm also getting this message:

Failed: [undefined]AssertionError: assert {'detail': [{'loc': ['query', 'ids'], 'msg': 'field required', 'type': 'value_error.missing'}]} == 200

What could that mean? Any help on towards where to look would be really appreciated.

Thank you for your support and time