@Test
  public void parsesResponseMissingLength() throws IOException {
    server.enqueue(new MockResponse().setChunkedBody("foo", 1));

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

    Response response = api.post("testing");
    assertThat(response.status()).isEqualTo(200);
    assertThat(response.reason()).isEqualTo("OK");
    assertThat(response.body().length()).isNull();
    assertThat(response.body().asInputStream())
        .hasSameContentAs(new ByteArrayInputStream("foo".getBytes(UTF_8)));
  }
Some client implementation tests should override this test if the PATCH operation is
unsupported.
core/src/test/java/feign/client/AbstractClientTest.java