test: that it sends the right headers

package.json

@@ -44,7 +44,6 @@
     "@types/jest": "^25.2.1",
     "husky": "^4.2.3",
     "jest": "^25.2.7",
-    "nock": "^12.0.3",
     "semantic-release": "^17.0.4",
     "ts-jest": "^25.3.1",
     "ts-loader": "^6.2.2",

src/createClient.spec.ts

@@ -1,9 +1,43 @@
-import { createClient, Client } from './createClient'
+import { createClient } from './createClient'
 
 describe('API Client', () => {
-	let client: Client
 	it('can be instantiated', () => {
-		client = createClient({ apiKey: 'some-api-key' })
+		const client = createClient({ apiKey: 'some-api-key' })
 		expect(client).toBeDefined()
 	})
+	it('sends the right headers', async () => {
+		const fetchMock = jest.fn(() => ({
+			status: 200,
+			json: async () => ({
+				_object: '/api/response',
+				self:
+					'https://api.flexport.com/shipments?page=1&per=20&sort=id&direction=desc',
+				version: 2,
+				data: {
+					_object: '/api/collections/paginated',
+					prev: null,
+					next: null,
+					data: null,
+				},
+				error: null,
+			}),
+		}))
+		const client = createClient({
+			apiKey: 'some-api-key',
+			fetchImplementation: fetchMock,
+		})
+
+		await client.listAllShipments()
+		expect(fetchMock).toHaveBeenCalledWith(
+			'https://api.flexport.com/shipments',
+			{
+				method: 'GET',
+				headers: {
+					Authorization: 'Bearer some-api-key',
+					'Content-Type': 'application/json',
+					'Flexport-Version': 2,
+				},
+			},
+		)
+	})
 })

src/createClient.ts

@@ -29,12 +29,14 @@ const handleResponse = async <A extends ApiResponseObject>(
 const get = <A extends ApiResponseObject>({
 	endpoint,
 	headers,
+	fetchImplementation,
 }: {
 	endpoint: string
 	headers: object
+	fetchImplementation?: any
 }) => async (resource: string): Promise<A> =>
 	handleResponse(
-		fetch(`${endpoint}/api/${resource}`, {
+		(fetchImplementation || fetch)(`${endpoint}/${resource}`, {
 			method: 'GET',
 			headers,
 		}),
@@ -43,14 +45,19 @@ const get = <A extends ApiResponseObject>({
 export const createClient = ({
 	apiKey,
 	endpoint,
+	fetchImplementation,
 }: {
 	apiKey: string
 	endpoint?: string
+	fetchImplementation?: any
 }): Client => {
-	const authorizedGet = <A extends ApiResponseObject>(resource: string) => () =>
+	const authorizedGet = <A extends ApiResponseObject>(
+		resource: string,
+	) => async () =>
 		get<A>({
 			headers: headers({ apiKey }),
 			endpoint: endpoint?.replace(/\/$/, '') || 'https://api.flexport.com',
+			fetchImplementation,
 		})(resource)
 	return {
 		listAllShipments: authorizedGet<Page<Shipment>>('shipments'),