### Question:
Assert { public static void assertNull(Object object) { if (imp != null && object != null) { imp.assertFailed(StringUtils.format("Expected 'null' but was '%s'", object)); } }  static void assertTrue(boolean condition); static void assertTrue(boolean condition, String message); static void assertTrue(boolean condition, String format, Object... args); static void assertFalse(boolean condition); static void assertFalse(boolean condition, String message); static void assertFalse(boolean condition, String format, Object... args); static T notNull(T reference); static void assertNotNull(Object object); static void assertNotNull(Object object, String message); static void assertNotNull(Object object, String format, Object... args); static void assertNull(Object object); static void assertNull(Object object, String message); static void assertNull(Object object, String format, Object... args); static void assertEquals(Object expected, Object actual); static void assertNotEquals(Object first, Object second); static void assertDispatchQueue(@NonNull DispatchQueue queue); static void assertMainThread(); static void assertBackgroundThread(); static void assertFail(String format, Object... args); static void assertFail(String message); static void setImp(AssertImp imp);  }### Answer:
@Test public void testAssertNull() throws Exception { AssertEx.assertNull(null); AssertEx.assertNull("foo"); AssertEx.assertNull(null); AssertEx.assertNull("foo", "assertNull(Object,String)"); AssertEx.assertNull(null, "", new Object()); AssertEx.assertNull("foo", "assertNull(Object,String,Object...)"); assertResult( "Expected 'null' but was 'foo'", "assertNull(Object,String)", "assertNull(Object,String,Object...)" ); }