Fix test typings

__mocks__/apollo-server-env.ts

@@ -1,18 +1,19 @@
+/// <reference types="jest" />
+
 import {
   fetch,
   Request,
   Response,
   BodyInit,
   Headers,
+  HeadersInit,
   URL,
   URLSearchParams,
-} from 'apollo-server-env';
+} from '../packages/apollo-server-env';
-
-type Headers = { [name: string]: string };
 
 interface FetchMock extends jest.Mock<typeof fetch> {
-  mockResponseOnce(data?: any, headers?: Headers, status?: number);
+  mockResponseOnce(data?: any, headers?: HeadersInit, status?: number);
-  mockJSONResponseOnce(data?: object, headers?: Headers);
+  mockJSONResponseOnce(data?: object, headers?: HeadersInit);
 }
 
 const mockFetch = jest.fn<typeof fetch>() as FetchMock;
@@ -42,11 +43,4 @@ mockFetch.mockJSONResponseOnce = (
   );
 };
 
-export = {
+export { mockFetch as fetch, Request, Response, Headers, URL, URLSearchParams };
-  fetch: mockFetch,
-  Request,
-  Response,
-  Headers,
-  URL,
-  URLSearchParams,
-};

packages/apollo-datasource-rest/src/__tests__/HTTPCache.test.ts

@@ -1,5 +1,4 @@
-import { fetch } from 'apollo-server-env';
+import { fetch } from '../../../../__mocks__/apollo-server-env';
-import { HTTPCache } from '../HTTPCache';
 
 import {
   mockDate,
@@ -7,6 +6,8 @@ import {
   advanceTimeBy,
 } from '../../../../__mocks__/date';
 
+import { HTTPCache } from '../HTTPCache';
+
 describe('HTTPCache', () => {
   let store: Map<string, string>;
   let httpCache: HTTPCache;

packages/apollo-datasource-rest/src/__tests__/RESTDataSource.test.ts

@@ -1,11 +1,11 @@
-import { fetch } from 'apollo-server-env';
+import { fetch } from '../../../../__mocks__/apollo-server-env';
 
 import {
   ApolloError,
   AuthenticationError,
   ForbiddenError,
 } from 'apollo-server-errors';
-import { RESTDataSource } from '../RESTDataSource';
+import { RESTDataSource, Request } from '../RESTDataSource';
 
 import { HTTPCache } from '../HTTPCache';