[RESTDataSource] Unable to run tests with Jest

Whenever I’m trying to run a test using a class that extends RESTDataSource and call the this.get(...) method, I have the following error TypeError: Cannot read property 'fetch' of undefined The thing is I want to test the real output of the request, so mocking the fetch method doesn’t seems to be an appropriate solution.

Some related files are: https://github.com/apollographql/apollo-server/blob/master/__mocks__/apollo-server-env.ts https://github.com/apollographql/apollo-server/blob/master/packages/apollo-datasource-rest/src/HTTPCache.ts#L11

How can I get ride of this error ? Is there any example that could show me how test a rest data source ?

[Borales]

@melkir try to call it like

const gApi = new GoogleAPI();
// this method is being called by ApolloServer
gApi.initialize({ context:{} }):

// your tests go below 
gApi.getGroups();

[iamam34]

I had the same issue. This line makes it compile with no typescript warnings:

import { KeyValueCache } from 'apollo-server-caching';
...
gApi.initialize({ context: {}, cache: {} as KeyValueCache });

But if you need a real cache to fix [TypeError: this.keyValueCache.get is not a function, use

import { InMemoryLRUCache } from 'apollo-server-caching';
...
gApi.initialize({ context: {}, cache: new InMemoryLRUCache() });