Getting Started

use : rely on EasyMock or Mockito and a test framework

Bypass Encapsulation mockパッケージを迂回

翻訳https://github.com/powermock/powermock/wiki/Bypass-Encapsulation

Quick summary

Whitebox
class provides a set of methods which could you help bypass encapsulation if it required. Usually, it's not a good idea to get/modify non-public fields, but sometimes it's only way to cover code by test for future refactoring.

Use Whitebox.setInternalState(..) to set a non-public member of an instance or class. 内部プライベートメンバーの設定

Use Whitebox.getInternalState(..) to get a non-public member of an instance or class. 社内プライベートメンバーの取得

Use Whitebox.invokeMethod(..) to invoke a non-public method of an instance or class. プライベートメソッド

を呼び出す

Use Whitebox.invokeConstructor(..) to create an instance of a class with a private constructor. プライベートコンストラクタ

を呼び出す

例を挙げる

1プライベートメソッド

を呼び出す.

private int sum(int a, int b) {
    return a+b;
}

int sum = Whitebox. invokeMethod(myInstance, "sum", 1, 2);

2プライベートメソッドリロード状況

...
private int myMethod(int id) {      
    return 2*id;
}

private int myMethod(Integer id) {      
        return 3*id;
}
...

入力パラメータclassに基づいてどれを使用するかを判断する

int result = Whitebox. invokeMethod(myInstance, new Class>[]{int.class}, "myMethod", 1);

3プライベートコンストラクタ

を呼び出す

public class PrivateConstructorInstantiationDemo {

    private final int state;

    private PrivateConstructorInstantiationDemo(int state) {
        this.state = state;
    }

    public int getState() {
        return state;
    }
}

呼び出し:

PrivateConstructorInstantiationDemo instance =  WhiteBox.invokeConstructor(
                PrivateConstructorInstantiationDemo.class, 43);

コンストラクタリロードの場合

public class PrivateConstructorInstantiationDemo {

    private final int state;

    private PrivateConstructorInstantiationDemo(int state) {
        this.state = state;
    }

    private PrivateConstructorInstantiationDemo(Integer state) {
              this.state = state;
              // do something else
    }

    public int getState() {
        return state;
    }
}

呼び出し:

PrivateConstructorInstantiationDemo instance = Whitebox.invokeConstructor(PrivateConstructorInstantiationDemo.class, new Class>[]{Integer.class}, 43);