@Test
 public void should_fail_if_given_key_is_null_but_actual_does_not_have_null_key() {
   try {
     maps.assertContainsKey(description, actual, null);
   } catch (AssertionError e) {
     verify(failures).failure(description, shouldContainKey(actual, null));
     return;
   }
   expectedAssertionErrorNotThrown();
 }
 @Test
 public void should_fail_if_actual_does_not_contain_key() {
   String key = "power";
   try {
     maps.assertContainsKey(description, actual, key);
   } catch (AssertionError e) {
     verify(failures).failure(description, shouldContainKey(actual, key));
     return;
   }
   expectedAssertionErrorNotThrown();
 }
 @Test
 public void should_fail_if_actual_is_null() {
   thrown.expect(AssertionError.class, actualIsNull());
   maps.assertContainsKey(description, null, "name");
 }
 @Test
 public void should_pass_if_actual_contains_null_key() {
   actual.put(null, "value");
   maps.assertContainsKey(description, actual, null);
 }
 @Test
 public void should_pass_if_actual_contains_given_key() {
   maps.assertContainsKey(description, actual, "name");
 }