下面是mock对象：public class MockSystemEnvironment implements Environmental {
private long currentTime;
public long getTime() {
return currentTime;
}
public void setTime(long currentTime) {
this.currentTime = currentTime;
}
public void playWavFile(String fileName) {
playedWav = true;
}
public boolean wavWasPlayed() {
return playedWav;
}
public void resetWav() {
playedWav = false;
}
}
下面是一个调用getTime的具体类： import java.util.Calendar;
public class Checker {
private Environmental env;
public Checker(Environmental env) {
this.env = env;
}
public void reminder() {
Calendar cal = Calendar.getInstance();
cal.setTimeInMills(env.getTime());
int hour = cal.get(Calendar.HOUR_OF_DAY);
if(hour >= 17) {
env.playWavFile("quit_whistle.wav");
}
}
}
使用env.getTime()的被测代码并不知道测试环境和真实环境之间的区别，因为它们都实现了相同的接口。现在，你可以借助mock对象，通过把时间设置为已知值，并检查行为是否如预期那样来编写测试。
import java.util.Calendar;
import junit.framework.TestCase;
public class TestChecker extends TestCase {
public void testQuittingTime() {
MockSystemEnvironment env = new MockSystemEnvironment();
Calendar cal = Calendar.getInstance();
cal.set(Calendar.YEAR, 2006);
cal.set(Calendar.MONTH, 11);
cal.set(Calendar.DAY_OF_MONTH,7);
cal.set(Calendar.HOUR_OF_DAY, 16);
cal.set(Calendar.MINUTE, 55);
long t1 = cal.getTimeInMillis();
env.setTime(t1);
Checker checker = new Checker(env);
checker.reminder();
assertFalse(env.wavWasPlayed());
t1 += (5*60*1000);
env.setTime(t1);
checker.reminder();
assertTrue(env.wavWasPlayed());
env.resetWav();
t1 += 2*60*60*1000;
env.setTime(t1);
checker.reminder();
assertTrue(env.wavWasPlayed());
}
}
(编辑:aniston)
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