How to test with custom ApolloClientOptions?

I'm trying to write a test using the ApolloTestingModule and ApolloClientOptions.

I provide custom ApolloClientOptions with the APOLLO_OPTION injection token. In the options I set the "no-cache" fetch-policy for my queries.

In my Test I import the ApolloTestingModule. When I run my test, I get the following error: "Error: Apollo has been already created." I'm not sure which part already created the default client but the ApolloTestingModule also tries to create the default client with the fake backend and a cache (that might be provided).

I made a local copy of the ApolloTestingModuleCore and modified the code a bit:

export class ApolloTestingModuleCore {
  constructor(
    apollo: Apollo,
    backend: ApolloTestingBackend,
    @Optional()
    @Inject(APOLLO_TESTING_CLIENTS)
    namedClients?: string[],
    @Optional()
    @Inject(APOLLO_TESTING_CACHE)
    cache?: ApolloCache<any>,
    @Optional()
    @Inject(APOLLO_TESTING_NAMED_CACHE)
    namedCaches?: any, // FIX: using NamedCaches here makes ngc fail
    @Optional()
    @Inject(APOLLO_OPTIONS)
      options?: ApolloClientOptions<any>,
  ) {
    function createOptions(name: string, c?: ApolloCache<any> | null) {
      return {
        ...options,
        link: new ApolloLink((operation) =>
          backend.handle(addClient(name, operation)),
        ),
        cache:
          c ||
          new InMemoryCache({
            addTypename: false,
          }),
      };
    }
     
    apollo.removeClient('default');
    apollo.create(createOptions('default', cache));

    if (namedClients && namedClients.length) {
      namedClients.forEach((name) => {
        const caches =
          namedCaches && typeof namedCaches === 'object' ? namedCaches : {};

        apollo.createNamed(name, createOptions(name, caches[name]));
      });
    }
  }
}

When I use the modified version of the ApolloTestingModuleCore everything works as expected.

Is it possible to change this part or is there an intended way to test with ApolloClientOptions?

The relevant entry point is packages/apollo-angular/testing/src/module.ts, specifically ApolloTestingModuleCore; start by tracing how APOLLO_OPTIONS is injected while ApolloTestingModule creates its default client. Reproduce the custom no-cache test described in the issue and verify that the options are honored without the “Apollo has been already created” error.