@Test
  public void registerListenerWithSignalAndNullSignalListenerThrowsNullPointerException() {
    assertThatThrownBy(
        () -> createSignalNotificationHandler().registerListener(null, Signal.SIGQUIT))
            .isInstanceOf(NullPointerException.class)
            .hasMessage(signalListenerForSignalCannotBeNullErrorMessage(Signal.SIGQUIT));
  }
Unit tests for {@link AbstractSignalNotificationHandler}.

@since GemFire 7.0
geode-core/src/test/java/org/apache/geode/internal/process/signal/AbstractSignalNotificationHandlerTest.java