public class Calc {
	static {
		System.out.println("hahaha");
	}

	public int add(int a, int b) {
		return interADD(a, b);
	}

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

	public int minus(int a, int b) {
		return interMinus(a, b);
	}
	
	public int interMinus(int a, int b) {
		return a-b;
	}
}

package com.kevin.util;

import static org.junit.Assert.*;
import junit.framework.Assert;

import org.easymock.EasyMock;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.powermock.api.easymock.PowerMock;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.core.classloader.annotations.SuppressStaticInitializationFor;
import org.powermock.modules.junit4.PowerMockRunner;

@RunWith(PowerMockRunner.class)
@PrepareForTest({Calc.class})
//suppress static initial
@SuppressStaticInitializationFor({"Calc.class"})
public class CalcTest {

	//mock private method in class that be testing
	@Test
	public void testAdd() {
		Calc createPartialMock = PowerMock.createPartialMock(Calc.class, "interADD");
		try {
			PowerMock.expectPrivate(createPartialMock, "interADD",2,3).andReturn(1000);
			PowerMock.replay(createPartialMock);
			int result = createPartialMock.add(2, 3);
			Assert.assertEquals(1000, result);
		} catch (Exception e) {
			// TODO Auto-generated catch block
			fail();
		}
	}
	
	//mock public method int class that be testing
	@Test
	public void testMinus() {
		Calc createPartialMock = PowerMock.createPartialMock(Calc.class, "interMinus");
		try {
			EasyMock.expect(createPartialMock.interMinus(5, 4)).andReturn(1000);
			EasyMock.replay(createPartialMock);
			int result = createPartialMock.minus(5, 4);
			Assert.assertEquals(1000, result);
		} catch (Exception e) {
			// TODO Auto-generated catch block
			fail();
		}
	}
}