尝试使用JMockit部分模拟类时,ClassLoader会抛出NullPointerException

时间:2011-11-10 20:45:30

标签: java unit-testing junit jmockit

使用Eclipse 3.6.1
Java 1.6.0_26
JMockit 0.999.10

更新:我能够创建一个SSCCE,我将在下面发布:

UPDATE2:添加了DaemonHelper。另外,如果我从构造函数中删除DaemonHelper,我会得到一个ClassCircularityError。有关?

当我从类加载器中获取NPE时,我正在尝试对类进行部分模拟,同时模拟类的几个依赖项。 NPE调用堆栈显示在下面

我有Daemon类,如此:

public class Daemon extends DaemonParent {

public Daemon(ConfigParent config, DaemonHelper helper) {
    super(config, helper);
}

@Override
public void execute() {
    log("Starting");
    if (config.test()) {
        log("Testing");
    }

    log("Ending");  
}
}

守护进程有一个像这样的父母:

public abstract class DaemonParent extends Thread {

protected ConfigParent config;
protected DaemonHelper helper;

public DaemonParent(ConfigParent config, DaemonHelper helper) {
    this.config = config;
    this.helper = helper;
}


public abstract void execute();

public void log(String s) {
    System.out.println(s);
}
}

有一个辅助类,如:

public class DaemonHelper extends Thread {

}

Config看起来像:

public class ConfigParent {

protected ConfigHelper helper;

public ConfigParent(ConfigHelper helper) {
    this.helper = helper;
}

public boolean test() {
    return false;
}
}

Config Parent看起来像:

public class ConfigParent implements Serializable {

protected ConfigHelper helper;

public ConfigParent(ConfigHelper helper) {
    this.helper = helper;
}

public boolean test() {
    return false;
}
}

测试看起来像:

public class DaemonTest {

@Test
public void testExecute(final ConfigHelper ch, final DaemonHelper dh) {
    final Config c = new Config(ch);
    final Daemon d = new Daemon(c, dh);

    new NonStrictExpectations(d) {
        {

        }
    };

    d.execute();

    new Verifications() {{
        d.log("Starting");
        d.log("Ending");
    }};
}
}

当我尝试运行此测试时,出现以下错误。请注意,当DaemonParent和Daemon Helper将java.lang.Thread作为超类时,只会弹出此错误:

java.lang.NullPointerException
at java.lang.Thread.interrupted(Unknown Source)
at sun.misc.Resource.getBytes(Unknown Source)
at java.net.URLClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.access$000(Unknown Source)
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at org.junit.internal.runners.model.EachTestNotifier.addFailure(EachTestNotifier.java:23)
at org.junit.runners.ParentRunner.run(ParentRunner.java:242)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:49)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)

我尝试评论NonStrictExpectations块和Verifications块,我得到了同样的错误。

NPE是从对currentThread()的调用中抛出的......我不知道它是如何失败的。

有什么想法吗?

1 个答案:

答案 0 :(得分:1)

事实证明守护进程的根超类是java.lang.Thread的问题导致JMockit遇到麻烦。解决方案是测试所需方法的静态部分模拟。

public class DaemonTest {

@Test
public void testExecute(final ConfigHelper ch, final DaemonHelper dh) {

new NonStrictExpectations(d) {
    @Mocked({"log"}
    Daemon d;
    @Mocked({"()"})
    DaemonHelper dh;
    {

    }
};


final Config c = new Config(ch);
final Daemon d = new Daemon(c, dh);
d.execute();

new Verifications() {{
    d.log("Starting");
    d.log("Ending");
}};
}
}