// Test with YAML
        OutputStream yamlOutput = SearchEngineUtil.getXContentBuilderOutputStream(callback, XContentType.YAML);
        assertNotNull(yamlOutput);
    }

    public void test_getXContentOutputStream_success() {
        ToXContent xContent = new ToXContent() {
            @Override
            public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {