java - JUnit 测试 : invoking parent class protected method

Question

这是我的类层次结构

abstract Class A
{
   int i = 0;
   protected init (String param1, String param2)
   {
       //do lots of common things based on param1, param2 and save data in i
   } 
}

然后有 3-4 个实现 A 的类，即

Class B extends A
{
    public B ()
    {
        super ();
    }

    public void performSomeAction ()
    {
        init (param1_specific_to_class_B, param2_specific_to_class_B); //calling parent class method 
        //do rest of teh random things
    }
}

现在，我正在尝试为 A 类编写一个 JUnit 测试。基本上我想测试 init 方法所做的是否准确。我试过了

Class clas = A.class;
B b = new B();

Method A_init;
A_init = clas.getDeclaredMethod("init", String.class, String.class);
A_init.invoke(b, param1_specific_to_class_B, param2_specific_to_class_B);

但它不起作用，我得到以下异常

java.lang.IllegalAccessException: Class test.package.subpackage.ATest can not access a member of class package.subpackage.A with modifiers "protected"
    at sun.reflect.Reflection.ensureMemberAccess(Reflection.java:65)
    at java.lang.reflect.Method.invoke(Method.java:578)
    at test.package.subpackage.ATest.initTest(ATest.java:49)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:585)

Answer 1

您可以将您的测试类放在与被测试类相同的包中。因此测试类将有权访问 protected 方法。

另一个更优雅的选择是使 protected 方法可访问:

A_init = clas.getDeclaredMethod("init", String.class, String.class);
A_init.setAccessible(true);
A_init.invoke(b, param1_specific_to_class_B, param2_specific_to_class_B);

希望对您有所帮助。