Apollo tests fail with --codeCoverage but pass without

Intended outcome: Running ng test --codeCoverage=true --no-watch should pass, since running without --codeCoverage passes

Actual outcome: The test fails with TypeError: Cannot read property 'use' of undefined this looks to be in (http://localhost:9877/_karma_webpack_/node_modules/apollo-angular/fesm2015/ngApollo.js:239:1). It seems Apollo is not being injected correctly.

How to reproduce the issue: When testing a Query from apollo-angular in a service (not a component) the tests will pass when run normally but will fail when generating code coverage. See the repository at https://github.com/aaraggornn/apollo-error-test for a reproduction.

Run npm run test to pass and npm run test:cc to fail (using --codeCoverage)

Versions “apollo-angular”: “^1.7.0”, “apollo-client”: “^2.6.4”, “typescript”: “~3.5.3”, “@angular/core”: “~8.2.8”, “graphql”: “^14.5.8”, “graphql-tag”: “^2.10.1”,

[nicky-lenaers]

@aaraggornn I have found a temporary workaround. You’ll need to inject Apollo manually in the extended Mutation class and call super() with the provided apollo instance:

import { Injectable } from '@angular/core';
import { Mutation, Apollo } from 'apollo-angular';
import gql from 'graphql-tag';

@Injectable({ providedIn: 'root' })
export class SomeMutationGQL extends Mutation {

  constructor(apollo: Apollo) {
    super(apollo); // <-- use this to prevent  the error from throwing
  }

  public document = gql`
    mutation ...
  `;
}

It will work with --codeCoverage turned on.

[aaraggornn]

This also happens with apollo-angular 1.8.0