Spring boot Throwing Exception test

@SpringBootTest
class StudentRepositoryTest {
    @Autowired
    Student student;
    @Autowired
    StudentGrades studentGrades;
	
    @MockBean
    private StudentRepository studentRepository;

    @Autowired
    private StudentService studentService;

    @Autowired
    private ApplicationContext context;


    @DisplayName("Throw runtime error")
    @Test
    void throwRuntimeError() {
        Student nullStudent = (Student)context.getBean("Student");
        doThrow(new RuntimeException()).when(studentRepository).checkNull(nullStudent);

        assertThrows(RuntimeException.class, ()-> {studentService.checkNUll(nullStudent); });

        verify(studentRepository, times(1)).checkNull(nullStudent);
    }

    @DisplayName("Multiple Stubbing")
    @Test
    void stubbingConsecutiveCalls() {
        Student nullStudent = (Student)context.getBean("Student");

        when(studentRepository.checkNull(nullStudent))
            .thenThrow(new RuntimeException())
            .thenReturn("Do not throw exception second time");
        
        assertThrows(RuntimeException.class, ()->{studentRepository.checkNull(nullStudent);});
        
        assertEquals("Do not throw exception second time", studentService.checkNull(nullStudent));

        verify(studentRepository, times(2)).checkNull(nullStudent);
    }


}