@Test void newBuilderWithPort_tooLargeIsInvalid() {
    Throwable exception = assertThrows(IllegalArgumentException.class, () -> {
      assertThat(Endpoint.newBuilder().port(65536).build().port()).isNull();
    });
    assertThat(exception.getMessage()).contains("invalid port 65536");
  }
The integer arg of port should be a whole number
zipkin/src/test/java/zipkin2/EndpointTest.java