你必须使用 间谍.这里的问题是您想验证一个方法是在 real 对象上调用的，而不是在模拟对象上调用的.你不能在这里使用模拟，因为它会存根类中的所有方法，因此也存根 countPerson 默认不做任何事情.

You will have to use a spy. The problem here is that you want to verify that a method was called on a real object, not on a mock. You can't use a mock here, since it will stub all the methods in the class, thereby stubbing also countPerson to do nothing by default.

@Test 
public void testCountPerson() {
    School school = School.getInstance();
    School spySchool = Mockito.spy(school);
    spySchool.countPerson(true);
    verify(spySchool).countIncludeTeacher();
}

但是，请注意，在使用间谍时应该非常小心，因为除非被存根，否则真正的方法是被调用的.引用 Mockito Javadoc:

However, note that you should be very careful when using spies because, unless stubbed, the real methods are gettings called. Quoting Mockito Javadoc:

应该小心偶尔使用真正的间谍，例如在处理遗留代码时.

Real spies should be used carefully and occasionally, for example when dealing with legacy code.