`onComplete` is not returning mocked data in mutation

I have the following code:

const [createPatient, { loading }] = useMutation(CREATE_PATIENT_MUTATION, {
  onCompleted: (data) => {
    const { patient } = data.createPatient;

    notificationQueue.add(uuid(), {
      type: "success",
      icon: "Success",
      title: `${userUtils.fullName(patient)} created`,
      description: "Patient was successfully created.",

When it succeeds, data.createPatient.patient populated during development. It works as expected.

However, in my tests it’s an empty object. I’ve verified the MockedProvider is using a complete response with a patient object, but it’s empty in the onComplete method anyway.

I came across this thread, but it’s been archived so I haven’t been able to ask any questions: `onCompleted` does not receive mocked data from MockedProvider · Issue #3899 · apollographql/react-apollo · GitHub