powermock example

MockConstructionTest.java

package demo.powermock;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.powermock.api.mockito.PowerMockito;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;

import static org.junit.Assert.*;

@RunWith(PowerMockRunner.class)
@PrepareForTest(XxxService.class)  //注意：非 XxxUtil.class
public class MockConstructionTest {

	/*
	 * 1.Use the @RunWith(PowerMockRunner.class) annotation at the class-level of the test case.
	 * 2.Use the @PrepareForTest(ClassThatCreatesTheNewInstance.class) annotation at the class-level of the test case.
	 * 3.PowerMockito.whenNew(MockNewClass.class)
	 * 4.Note : withArguments(value), value必须与实际new时的参数类型相同
	 */
	
	@Test
	public void mockConstruction() throws Exception {
		//prepare
		XxxService service = new XxxService();
		XxxUtil util = new XxxUtil();
		String name = "hello";
		util.setName(name);
		PowerMockito.whenNew(XxxUtil.class).withNoArguments().thenReturn(util);
		
		//action
		XxxUtil res = service.getUtil();
		
		//assert
		assertEquals(name, res.getName());
	}
	
}

MockFinalMethodOrClassTest.java

package demo.powermock;

/**
 * 请大家自己测试
 * @author bohan.sj
 */
public class MockFinalMethodOrClassTest {

}

MockJavaCoreLibraryTest.java

package demo.powermock;

import static org.mockito.Matchers.anyLong;
import static org.mockito.Mockito.*;

import java.io.File;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.powermock.api.mockito.PowerMockito;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;

@RunWith(PowerMockRunner.class)
@PrepareForTest(XxxUtil.class)  // 注意：非 Thread.class 
public class MockJavaCoreLibraryTest {

	@Test
	public void mockJavaCoreLibrary() throws Exception {
		//prepare
		PowerMockito.mockStatic(Thread.class);
		
		//action
		XxxUtil.sleep(1000);
		
		//assert
		PowerMockito.verifyStatic(times(1));
		Thread.sleep(anyLong());
	}
	
	/**
	 * 关键点：withArguments(value), value必须与实际new时的参数相同
	 * @throws Exception
	 */
	@Test
	public void readFile$mockNewFile() throws Exception {
		//preapare
		File file = mock(File.class);
		PowerMockito.whenNew(File.class).withArguments(anyString()).thenReturn(file);
		
		//action
		XxxUtil.readFile(anyString());
		
		//assert
		verify(file, times(1)).getAbsolutePath();
	}
	
}

MockPartialMethodTest.java

package demo.powermock;

import static org.junit.Assert.assertFalse;
import static org.mockito.Matchers.anyInt;
import static org.mockito.Mockito.times;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.powermock.api.mockito.PowerMockito;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;

// We prepare XxxServiceClass for test because it's final or we need to mock private or static methods
@RunWith(PowerMockRunner.class)
@PrepareForTest(XxxService.class)  // spy是不需要声明 @PrepareForTest，但必须使用 doReturn("foo").when(spy).get(0);
public class MockPartialMethodTest {
	
	private XxxService service = new XxxService();
	
	@Test 
	public void mockPartialPrivateMethod() throws Exception {
		//prepare
		service = PowerMockito.spy(service);
		PowerMockito.doReturn(false).when(service, "isNeedHandle", anyInt()); // mock private method
		
		/*
		* spy must use doReturn()
		*
		List list = new LinkedList();
		List spy = spy(list);
		//Impossible: real method is called so spy.get(0) throws IndexOutOfBoundsException (the list is yet empty)
		when(spy.get(0)).thenReturn("foo");
		
		//You have to use doReturn() for stubbing
		doReturn("foo").when(spy).get(0);
		*/
		
		//action
		boolean res = service.handle(2);
		
		//assert
		assertFalse(res); 
		PowerMockito.verifyPrivate(service, times(1)).invoke("isNeedHandle", anyInt());
	}

}

MockStaticMethodTest.java

package demo.powermock;

import static org.junit.Assert.assertFalse;
import static org.mockito.Matchers.anyInt;
import static org.mockito.Mockito.times;
import static org.mockito.Mockito.when;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.powermock.api.mockito.PowerMockito;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;

@RunWith(PowerMockRunner.class)
@PrepareForTest(XxxUtil.class)
public class MockStaticMethodTest {
	
	@Test
	public void mockStaticMethodAndVerifyStaticMethod() {
		//prepare
		XxxService service = new XxxService();
		PowerMockito.mockStatic(XxxUtil.class);
		when(XxxUtil.isSafe(anyInt())).thenReturn(false);
		
		//action
		boolean res = service.isAllowBuy(2);
		
		//assert
		assertFalse(res);
		
		/*
		 * 提示：静态方法verify有点别扭，如下是官方示例
		 * 
		// Different from Mockito, always use PowerMockito.verifyStatic() first
        PowerMockito.verifyStatic(Mockito.times(2));
        // Use EasyMock-like verification semantic per static method invocation
        Static.firstStaticMethod(param);

        // Remember to call verifyStatic() again
        PowerMockito.verifyStatic(Mockito.never());
        Static.secondStaticMethod();
		 */
		PowerMockito.verifyStatic(times(1));
		XxxUtil.isSafe(anyInt());
 	}
	
	@Test(expected=RuntimeException.class)
	public void mockStaticMethodThrowException() {
		//prepare
		XxxService service = new XxxService();
		PowerMockito.mockStatic(XxxUtil.class);
		PowerMockito.doThrow(new RuntimeException()).when(XxxUtil.isSafe(anyInt()));
		
		//action
		service.isAllowBuy(2);
	}

}

PrivateFieldOrMethodTest.java

package demo.powermock;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;
import static org.mockito.Matchers.anyInt;
import static org.mockito.Mockito.times;

import java.lang.reflect.Field;
import java.lang.reflect.Method;

import org.junit.Before;
import org.junit.Test;
import org.powermock.api.mockito.PowerMockito;

/**
 * 注：当然可用反射实现同样目的，可认为powermock帮你提供工具类
 * @author bohan.sj
 */
public class PrivateFieldOrMethodTest {
	
	private XxxService target;
	
	@Before
	public void setUp() {
		target = new XxxService();
	}
	
	@Test
	public void modifyPrivateField() throws Exception {
		//prepare
		Field f = PowerMockito.field(XxxService.class, "threshold");
		f.set(null, 10);
		
		//action
		int result = target.sum();
		
		//assert
		assertEquals(10, result);
	}
	
	@Test
	public void testPrivateMethod() throws Exception {
		//preapre
		Method m = PowerMockito.method(XxxService.class, "isPositiveNumber", new Class[]{int.class});
		
		//action
		boolean res = (Boolean)m.invoke(target, 2);
		
		//assert
		assertTrue(res);
	}
	
	@Test
	public void verifyPrivateMethodInvoke() throws Exception {
		//prepare
		
		//action
		target.foreach(2);
		
		//assert
		PowerMockito.verifyPrivate(target, times(2)).invoke("isPositiveNumber", anyInt());
	}
	
}

XxxService.java

package demo.powermock;


public class XxxService {
	
	/* 
	 * 1.修改私有域
	 * 	- unit test 必须保证 '快'，需要修改private field
	 */
	private static int threshold = 1000000;
	public int sum() {
		int i=0;
		while(i < threshold) {
			i=i+1;
		}
		return i;
	}
	
	/*
	 * 2.测试私有方法
	 */
	private boolean isPositiveNumber(int i) {
		if(i > 0) {
			return true;
		} else {
			return false;
		}
	}
	
	/*
	 * 3.无返回值，校验：对某方法调用次数
	 */
	public void foreach(int count) {
		for(int i=0; i<count; i++) {
			isPositiveNumber(i);
		}
	}
	
	/*
	 * 3.mock静态方法
	 */
	public boolean isAllowBuy(int i) {
		//判断是否安全
		if(XxxUtil.isSafe(i)) {
			//判断是否超过支付能力
			// ....
		}
		return false;
	}
	
	/*
	 * 4.mock partial method
	 *  - 需要mock isNeedHandle()，否则导致单元测试粒度太大
	 */
	public boolean handle(int i) {
		if(isNeedHandle(i)) {
			// ... logic handle
			return true;
		}
		return false;
	}
	private boolean isNeedHandle(int i) {
		//假设此方法逻辑，依赖外部服务、且逻辑较复杂
		return true;
	}
	
	
	/*
	 * 5.mock construction
	 */
	public XxxUtil getUtil() {
		XxxUtil util = new XxxUtil();
		return util;
	}

}

XxxUtil.java

package demo.powermock;

import java.io.File;


public class XxxUtil {

	public static boolean isSafe(int i) {
		if(i > 0) {
			return true;
		} else {
			return false;
		}
	}
	
	private String name = "XxxUtil";
	public String getName() {
    	return name;
    }
	public void setName(String name) {
    	this.name = name;
    }
	
	/*
	 * 1. mock java core library
	 *  - 无结果返回，只能verify方法是否被调用
	 *  - 且是Java自身类
	 */
	public static void sleep(long time) throws Exception {
		Thread.sleep(time);
	}
	
	/*
	 * 2. mock java core library
	 *  - new instance
	 */
	public static void readFile(String filename) throws Exception {
		File file = new File(filename);
		System.out.println(file.getAbsolutePath());
	}
	
}

The static method at MockJavaCoreLibraryTest.java L21 is not mocking any method. How can we mock a static method?

gradle 要怎么依赖？