http getを testで実行する

http_get.dart

  setUpAll(() => HttpOverrides.global = null);

  test('http get', () async {

    var url = Uri.https('official-joke-api.appspot.com', 'jokes/random');

    var response = await http.get(url);
    expect(response.statusCode, 200);
    debugPrint(response.body);
  });