### Question:
Assertions { public static void assertNotNull(Object object, String message) { if (object == null) { throw new IllegalArgumentException(message); } } private  Assertions(); static void assertNotNull(Object object, String message); static void assertHasText(String string, String message);  }### Answer:
@Test public void assertNotNull_throwsIllegalArgumentExceptionContainingMessage() { String message = "A message"; assertThatThrownBy(() -> { Assertions.assertNotNull(null, message); }).isInstanceOf(IllegalArgumentException.class).hasMessage(message); }
@Test public void assertNotNull_doesNotThrow() { Assertions.assertNotNull(new Object(), "Should not be thrown"); }