@Test
public void attemptToReadErrorResponse_plainString() throws Exception {

    final String errMsg = "some response";
    final byte[] bytes = errMsg.getBytes(StandardCharsets.UTF_8);
    final HttpClientResponse<ByteBuf> resp = response(Unpooled.copiedBuffer(bytes), (headers) -> {
        headers.add("Content-Type", "text/plain;charset=utf-8");
        headers.add("Content-Length", bytes.length);
    });
    final String err = ResponseUtils.attemptToReadErrorResponse(resp).toBlocking().first();
    assertThat(err).isEqualTo(errMsg);
}