@Test
  void producesWithHeaderParamContainAllHeaders() throws Exception {
    assertThat(
            parseAndValidateMetadata(
                    mixedAnnotationsClass(),
                    "getWithHeaders",
                    String.class,
                    String.class,
                    String.class)
                .template())
        .hasHeaders(entry("Accept", Arrays.asList("application/json", "{Accept}")))
        .hasQueries(
            entry("multiple", Arrays.asList("stuff", "{multiple}")),
            entry("another", Collections.singletonList("{another}")));
  }
Body type is only for the body param.
jaxrs/src/test/java/feign/jaxrs/JAXRSContractTestSupport.java