### Question:
ProcessorMessage { public ProcessorMessage atAnnotation(AnnotationMirror annotationMirror) { Objects.requireNonNull(element, "ProcessorMessage#element must be set in order to set an annotation"); this.annotationMirror = annotationMirror; return this; } ProcessorMessage(Diagnostic.Kind kind, String format, Object... args); ProcessorMessage atElement(Element element); ProcessorMessage atAnnotation(AnnotationMirror annotationMirror); ProcessorMessage atAnnotation(Class<? extends Annotation> annotation); ProcessorMessage atAnnotationValue(AnnotationValue annotationValue); ProcessorMessage atAnnotationValue(String attributeName);  }### Answer:
@Test void atAnnotation_elementNotSetAnnotationMirror_throwsNullPointerException() { assertThatThrownBy(() -> createInstance().atAnnotation(annotationMirrorMock)) .isInstanceOf(NullPointerException.class); }
@Test void atAnnotation_elementNotSetClass_throwsNullPointerException() { assertThatThrownBy(() -> createInstance().atAnnotation(Test.class)) .isInstanceOf(NullPointerException.class); }