### Question:
Assert { public static <T> T assertNull(T object) { return assertNull(object, null, null, (Object[]) null); }  static T assertNotNull(T object); static T assertNotNull(T object, String message, Object...args); static T assertNotNull(T object, ExceptionType exceptionType, String message, Object...args); static T assertNull(T object); static T assertNull(T object, String message, Object...args); static T assertNull(T object, ExceptionType exceptionType, String message, Object...args); static void assertTrue(boolean expression); static void assertTrue(boolean expression, String message, Object...args); static void assertTrue(boolean expression, ExceptionType exceptionType, String message, Object...args); static T unreachableCode(); static T unreachableCode(String message, Object...args); static T unexpectedException(Throwable e); static T unexpectedException(Throwable e, String message, Object...args); static T fail(); static T fail(String message, Object...args); static T unsupportedOperation(); static T unsupportedOperation(String message, Object...args);  }### Answer:
@Test public void assertNull() { Assert.assertNull(null); try { Assert.assertNull(OBJECT); } catch (IllegalArgumentException e) { assertThat(e, exception(IllegalArgumentException.class, DEFAULT_HEADER, "must be null")); } Assert.assertNull(null, MESSAGE); try { Assert.assertNull(OBJECT, MESSAGE); } catch (IllegalArgumentException e) { assertThat(e, exception(IllegalArgumentException.class, MESSAGE)); } try { Assert.assertNull(OBJECT, MESSAGE, 1); } catch (IllegalArgumentException e) { assertThat(e, exception(IllegalArgumentException.class, MESSAGE_1)); } Assert.assertNull(null, Assert.ExceptionType.ILLEGAL_STATE, MESSAGE); try { Assert.assertNull(OBJECT, Assert.ExceptionType.ILLEGAL_STATE, MESSAGE); } catch (IllegalStateException e) { assertThat(e, exception(IllegalStateException.class, MESSAGE)); } try { Assert.assertNull(OBJECT, Assert.ExceptionType.ILLEGAL_STATE, MESSAGE, 1); } catch (IllegalStateException e) { assertThat(e, exception(IllegalStateException.class, MESSAGE_1)); } }