PowerMock + Mockito

Writing unit tests can be hard and sometimes good design has to be sacrificed for the sole purpose of testability.

Often testability corresponds to good design, but this is not always the case.

For example final classes and methods cannot be used, private methods sometimes need to be protected or unnecessarily moved to a collaborator, static methods should be avoided completely and so on simply because of the limitations of existing frameworks.

PowerMock is a framework that extend other mock libraries such as PowerMock with more powerful capabilities.

 

Write a test like this:

@RunWith(PowerMockRunner.class)
@PrepareForTest( { YourClassWithEgStaticMethod.class })
public class YourTestCase {
      ...
}

 

一个读取文本文件字符的Tools：

package wei.peng.easymock;

import java.io.BufferedReader;
import java.io.FileReader;

/**
 * 逐行读取文本文件，计算字符数
 * @author WPeng
 */
public class BeMockObject2 {
	int resultNum = 0;
	
	public int getCharNum(){
		try {
			String pathStr = "c:/test.txt";
			
			//创建FileReader对象，用来读取字符流
			FileReader fileReader = new FileReader(pathStr);
			//缓冲指定文件的输入
			BufferedReader bufferReader = new BufferedReader(fileReader);
			
			//一行一行读
			while (bufferReader.ready()) {
				String line = bufferReader.readLine();
				resultNum += line.length();
			}
			
		} catch (Exception e) {
			// TODO: handle exception
		}
		
		return resultNum; 
	}
}

 PowerMock + Mockito测试：

package wei.peng.easymock;

import junit.framework.TestCase;
import static org.mockito.Mockito.when;

import org.junit.Before;
import org.junit.runner.RunWith;
import org.mockito.Mock;
import org.mockito.MockitoAnnotations;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;

/**
 * @author WPeng
 */
@RunWith(PowerMockRunner.class)
@PrepareForTest(BeMockObject2.class)
public class MockitoTest extends TestCase {

	@Mock
	BeMockObject2 beMockObject2;

	@Before
	public void init() {
		MockitoAnnotations.initMocks(this);
	}

	public void testGetRecordNum() {
		int expected = 100;
		when(beMockObject2.getCharNum()).thenReturn(100);

		assertEquals(expected, beMockObject2.getCharNum());
	}

}