fix fetch mock (#9)

package.json

@@ -18,8 +18,8 @@
   "devDependencies": {
     "@types/jest": "^26.0.23",
     "@types/node": "14.14.x",
-    "fetch-mock-jest": "^1.5.1",
     "jest": "^26.6.3",
+    "jest-fetch-mock": "^3.0.3",
     "jest-websocket-mock": "^2.2.0",
     "mock-socket": "^9.0.3",
     "ts-jest": "^26.5.6",

test/api.ts

-import fetchMock from 'fetch-mock-jest';
 import { request } from '../src/api';
+import { enableFetchMocks } from 'jest-fetch-mock';
+
+enableFetchMocks();
+
+function getFetchCall(call: any[]) {
+	const { body, method } = call[1];
+	if (body != null && typeof body != 'string') {
+		throw new Error('invalid body');
+	}
+	return {
+		url: call[0],
+		method: method,
+		body: JSON.parse(body as any)
+	};
+}
 
 describe('API', () => {
 	test('success', async () => {
-		fetchMock
-			.post('https://misskey.test/api/i', (url, options) => {
-				if (typeof options.body.i === 'string') {
-					return {
-						body: {
-							id: 'foo'
-						}
-					};
+		fetchMock.resetMocks();
+		fetchMock.mockResponse(async (req) => {
+			const body = await req.json();
+			if (req.method == 'POST' && req.url == 'https://misskey.test/api/i') {
+				if (typeof body.i != 'string') {
+					return { status: 400 };
 				}
-				return 400;
-			});
+				return JSON.stringify({ id: 'foo' });
+			} else {
+				return { status: 404 };
+			}
+		});
 
 		const res = await request('https://misskey.test', 'i', {}, 'TOKEN');
 
+		// validate response
 		expect(res).toEqual({
 			id: 'foo'
 		});
 
-		expect(fetchMock).toHaveLastFetched({
+		// validate fetch call
+		expect(getFetchCall(fetchMock.mock.calls[0])).toEqual({
 			url: 'https://misskey.test/api/i',
+			method: 'POST',
 			body: { i: 'TOKEN' }
-		}, 'post');
+		});
 	});
 });