More descriptive error feedback for error 'No more mocked responses for the query'

[oliverjohns]

Writing tests for Apollo is gruesome due to this unintuitive error. Whenever one mocks a query or mutation, if the mock isn't exactly the same as the real one, the error 'No more mocked responses for the query' is thrown.

The issue is that this error doesn't state what the discrepancy is between the mock and the real query, which leads to a lot of time being spent double-checking mocks and queries. For complex queries this can be a real time sink.

This error should point out what exactly is not matching. This would save testers a ton of time.

[jpvajda]

👋 I'm going to close this out, as we have an umbrella issue tracking testing improvements here apollographql/apollo-client#9738