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

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

    assertThat(api.patch("")).isEqualTo("foo");

    MockWebServerAssertions.assertThat(server.takeRequest())
        .hasHeaders(
            entry("Accept", Collections.singletonList("text/plain")),
            entry("Content-Length", Collections.singletonList("0")))
        .hasNoHeaderNamed("Content-Type")
        .hasMethod("PATCH");
  }
Some client implementation tests should override this test if the PATCH operation is
unsupported.
core/src/test/java/feign/client/AbstractClientTest.java