@Test
  public void defaultCollectionFormat() throws Exception {
    server.enqueue(new MockResponse().setBody("body"));

    TestInterface api =
        newBuilder().target(TestInterface.class, "http://localhost:" + server.getPort());

    Response response = api.get(Arrays.asList("bar", "baz"));

    assertThat(response.status()).isEqualTo(200);
    assertThat(response.reason()).isEqualTo("OK");

    MockWebServerAssertions.assertThat(server.takeRequest())
        .hasMethod("GET")
        .hasPath("/?foo=bar&foo=baz");
  }
Some client implementation tests should override this test if the PATCH operation is
unsupported.
core/src/test/java/feign/client/AbstractClientTest.java