public static <Req extends MessagingRequest> Matcher<Req> channelNameEquals(String channelName) {
    if (channelName == null) throw new NullPointerException("channelName == null");
    if (channelName.isEmpty()) throw new NullPointerException("channelName is empty");
    return new MessagingChannelNameEquals<Req>(channelName);
  }
@Test void channelNameEquals_unmatched() {
    when(request.channelName()).thenReturn("complaints");

    assertThat(channelNameEquals("alerts").matches(request)).isFalse();
  }