assertNotNull(yamlOutput);
    }

    @Test
    public void test_getXContentOutputStream_success() {
        ToXContent xContent = new ToXContent() {
            @Override
            public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
                builder.startObject();
                builder.field("content", "test");

    public void visit(final QueryBuilderVisitor visitor) {
        queryBuilder.visit(visitor);
    }

    @Override
    public XContentBuilder toXContent(final XContentBuilder builder, final Params params) throws IOException {
        return queryBuilder.toXContent(builder, params);
    }

    @Override
    public void writeTo(final StreamOutput out) throws IOException {
        queryBuilder.writeTo(out);
    }

            final XContentBuilder builder = XContentFactory.jsonBuilder();
            builder.startObject();
            response.toXContent(builder, ToXContent.EMPTY_PARAMS);
            builder.endObject();
            builder.flush();
            try (OutputStream out = builder.getOutputStream()) {