如何对同步代码进行单元测试 [英] How to unit test synchronized code
问题描述
我是Java和junit的新手.我有以下要测试的代码.如果您能提出有关测试它的最佳方法的想法,将不胜感激.
I am new to Java and junit. I have the following peice of code that I want to test. Would appreciate if you could send your ideas about what's the best way to go about testing it.
基本上,以下代码与从集群中选出领导者有关.领导者对共享缓存持有锁定,并且如果领导者以某种方式释放了对缓存的锁定,则领导者的服务将恢复并处置.
Basically, the following code is about electing a leader form a Cluster. The leader holds a lock on the shared cache and services of the leader get resumed and disposed if it somehow looses the lock on the cache.
我如何确保领导者/线程仍保持对缓存的锁定,并且确保另一个线程在第一个线程执行期间无法恢复其服务?
How can i make sure that a leader/thread still holds the lock on the cache and that another thread cannot get its services resumed while the first is in execution?
public interface ContinuousService {
public void resume();
public void pause();
}
public abstract class ClusterServiceManager {
private volatile boolean leader = false;
private volatile boolean electable = true;
private List<ContinuousService> services;
protected synchronized void onElected() {
if (!leader) {
for (ContinuousService service : services) {
service.resume();
}
leader = true;
}
}
protected synchronized void onDeposed() {
if (leader) {
for (ContinuousService service : services) {
service.pause();
}
leader = false;
}
}
public void setServices(List<ContinuousService> services) {
this.services = services;
}
@ManagedAttribute
public boolean isElectable() {
return electable;
}
@ManagedAttribute
public boolean isLeader() {
return leader;
}
public class TangosolLeaderElector extends ClusterServiceManager implements Runnable {
private static final Logger log = LoggerFactory.getLogger(TangosolLeaderElector.class);
private String election;
private long electionWaitTime= 5000L;
private NamedCache cache;
public void start() {
log.info("Starting LeaderElector ({})",election);
Thread t = new Thread(this, "LeaderElector ("+election+")");
t.setDaemon(true);
t.start();
}
public void run() {
// Give the connection a chance to start itself up
try {
Thread.sleep(1000);
} catch (InterruptedException e) {}
boolean wasElectable = !isElectable();
while (true) {
if (isElectable()) {
if (!wasElectable) {
log.info("Leadership requested on election: {}",election);
wasElectable = isElectable();
}
boolean elected = false;
try {
// Try and get the lock on the LeaderElectorCache for the current election
if (!cache.lock(election, electionWaitTime)) {
// We didn't get the lock. cycle round again.
// This code to ensure we check the electable flag every now & then
continue;
}
elected = true;
log.info("Leadership taken on election: {}",election);
onElected();
// Wait here until the services fail in some way.
while (true) {
try {
Thread.sleep(electionWaitTime);
} catch (InterruptedException e) {}
if (!cache.lock(election, 0)) {
log.warn("Cache lock no longer held for election: {}", election);
break;
} else if (!isElectable()) {
log.warn("Node is no longer electable for election: {}", election);
break;
}
// We're fine - loop round and go back to sleep.
}
} catch (Exception e) {
if (log.isErrorEnabled()) {
log.error("Leadership election " + election + " failed (try bfmq logs for details)", e);
}
} finally {
if (elected) {
cache.unlock(election);
log.info("Leadership resigned on election: {}",election);
onDeposed();
}
// On deposition, do not try and get re-elected for at least the standard wait time.
try { Thread.sleep(electionWaitTime); } catch (InterruptedException e) {}
}
} else {
// Not electable - wait a bit and check again.
if (wasElectable) {
log.info("Leadership NOT requested on election ({}) - node not electable",election);
wasElectable = isElectable();
}
try {
Thread.sleep(electionWaitTime);
} catch (InterruptedException e) {}
}
}
}
public void setElection(String election) {
this.election = election;
}
@ManagedAttribute
public String getElection() {
return election;
}
public void setNamedCache(NamedCache nc) {
this.cache = nc;
}
推荐答案
作为测试框架的替代方法(或者,如果使用JUnit,可以替代JUnit上的其他扩展),只是一些简单的旧代码:
As an alternative to testing frameworks (or to extra extensions on top of JUnit, if you are using that) is just some plain old code:
- 创建多个线程并将其应用于该例程.
- 遍历线程并测试每个线程,直到找出谁是领导者为止.
- 对程序的状态应用不同的环境变化(包括时间的流逝)并重做测试.领导者仍然是领导者吗?
- 现在,强制领导退位(杀死该线程或其他东西).另一个线程接管了吗?
这篇关于如何对同步代码进行单元测试的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!