mockGraphQLMutation not calling onCompleted in unit test

I’m currently using mockGraphQLMutation in a unit test I’m writing for one of my pages. The below isn’t exact code, but similar enough:

it('some test', () => {
  mockGraphQLMutation('UpdateUserMutation', () => {
    return {
      id: 1,
      name: 'Bob',

Now in the page with the mutation, I’m using the useMutation hook:

const [UpdateUserMutation] = useMutation(
      onCompleted: () => {

I’m testing in my unit test that the onCompleted function is being called – specifically I’ve mocked the navigate function and am asserting it’s called at least once, but I’m not seeing that behavior. Is there anything I might be doing wrong here?