java - 通过Enum对Singleton进行单元测试会抛出java.lang.NoClassDefFoundError

这很奇怪，我不知道如何解释清楚。请耐心等待，并查看代码段以获取详细信息。

我使用枚举实现了单例。枚举有一个私有构造函数，在构造对象之前，我在其中进行了一些操作和验证。对于所有这些验证，我抛出一些异常（如IllegalArgumentException）。

我的测试用例包括对负面和正面场景的测试。每当有超过2个测试用例混合了负面和正面测试用例时，我会遇到以下异常：java.lang.NoClassDefFoundError: Could not initialize class com.blah.blah.SingletonClass。请查看下面的完整代码。我正在使用以下技术堆栈：

JDK 1.7_51
Spring 4.0.0.RELEASE
testng 6.8.7

SingletonUsingEnum.java

public enum SingletonUsingEnum {
  INSTANCE;

  // Logger
  private final Logger logger = LoggerFactory.getLogger(SingletonUsingEnum.class);

  private SingletonUsingEnum() {
    final MyConfig myConfig = MyConfigManager.getMyConfig();
    if(myConfig == null) {
      throw new IllegalArgumentException("MyConfig is null");
    }

    if(StringUtils.isBlank(myConfig.getConfigValue())) {
      throw new IllegalArgumentException("myConfig.configValue value null/empty");
    }

    if(StringUtils.isBlank(myConfig.getOtherConfigValue())) {
      throw new IllegalArgumentException("myConfig.otherConfigValue null/empty");
    }

    logger.info("This is a singleton using enum");
  } 
}

MyConfig.java

public class MyConfig {
  private String configValue;
  private String otherConfigValue;

  public MyConfig(final String configValue, final String otherConfigValue) {
    this.configValue = configValue;
    this.otherConfigValue = otherConfigValue;
  }

  public String getConfigValue() {
    return configValue;
  }

  public String getOtherConfigValue() {
    return otherConfigValue;
  } 
}

MyConfigManager.java

public class MyConfigManager {
  private final static ConcurrentMap myConfigHolder = new ConcurrentHashMap();

  public static void registerMyConfig(final MyConfig myConfig) {
    myConfigHolder.put("myConfig", myConfig);
  }

  public static MyConfig getMyConfig() {
    return myConfigHolder.get("myConfig");
  }

  public static void clearAll() {
    myConfigHolder.clear();
  }
}

SingletonUsingEnumTest.java

@ContextConfiguration(classes = {SingletonUsingEnumTest.SpringConfig.class})
public class SingletonUsingEnumTest extends AbstractTestNGSpringContextTests {
  // Logger
  private static final Logger logger = LoggerFactory.getLogger(SingletonUsingEnumTest.class);

  @AfterMethod
  public void cleanUp() {
    MyConfigManager.clearAll();
  }

  @Test(expectedExceptions = {IllegalArgumentException.class, ExceptionInInitializerError.class})
  public void nullMyConfig() {
    MyConfigManager.registerMyConfig(new MyConfig("", ""));
    final SingletonUsingEnum singleton = SingletonUsingEnum.INSTANCE;
  }

  @Test
  public void validMyConfig_nullConfigValue() {
    MyConfigManager.registerMyConfig(new MyConfig("", "b"));
    final SingletonUsingEnum singleton = SingletonUsingEnum.INSTANCE;
  }

  @Test(dependsOnMethods = {"nullMyConfig"})
  public void allValidData() {
    MyConfigManager.registerMyConfig(new MyConfig("a", "b"));
    final SingletonUsingEnum singleton = SingletonUsingEnum.INSTANCE;
  }

  @Configuration
  @EnableAspectJAutoProxy(proxyTargetClass = true)
  public static class SpringConfig {

  }
}

测试执行结果如下所示。我故意在第一次测试中添加了expectedExceptions来隐藏第一次测试的堆栈跟踪。

[TestNG] Running:
  /private/var/folders/l6/hmmqvjpj13ggmyc69sk1s5740000gn/T/testng-eclipse-135911498/testng-customsuite.xml

PASSED: nullMyConfig
FAILED: validMyConfig_nullConfigValue
java.lang.NoClassDefFoundError: Could not initialize class com.demo.singleton.SingletonUsingEnum
    at com.demo.singleton.SingletonUsingEnumTest.validMyConfig_nullConfigValue(SingletonUsingEnumTest.java:38)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.testng.internal.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:84)
    at org.testng.internal.MethodInvocationHelper$1.runTestMethod(MethodInvocationHelper.java:200)
    at org.springframework.test.context.testng.AbstractTestNGSpringContextTests.run(AbstractTestNGSpringContextTests.java:157)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.testng.internal.MethodInvocationHelper.invokeHookable(MethodInvocationHelper.java:212)
    at org.testng.internal.Invoker.invokeMethod(Invoker.java:707)
    at org.testng.internal.Invoker.invokeTestMethod(Invoker.java:901)
    at org.testng.internal.Invoker.invokeTestMethods(Invoker.java:1231)
    at org.testng.internal.TestMethodWorker.invokeTestMethods(TestMethodWorker.java:127)
    at org.testng.internal.TestMethodWorker.run(TestMethodWorker.java:111)
    at org.testng.TestRunner.privateRun(TestRunner.java:767)
    at org.testng.TestRunner.run(TestRunner.java:617)
    at org.testng.SuiteRunner.runTest(SuiteRunner.java:334)
    at org.testng.SuiteRunner.runSequentially(SuiteRunner.java:329)
    at org.testng.SuiteRunner.privateRun(SuiteRunner.java:291)
    at org.testng.SuiteRunner.run(SuiteRunner.java:240)
    at org.testng.SuiteRunnerWorker.runSuite(SuiteRunnerWorker.java:52)
    at org.testng.SuiteRunnerWorker.run(SuiteRunnerWorker.java:86)
    at org.testng.TestNG.runSuitesSequentially(TestNG.java:1224)
    at org.testng.TestNG.runSuitesLocally(TestNG.java:1149)
    at org.testng.TestNG.run(TestNG.java:1057)
    at org.testng.remote.RemoteTestNG.run(RemoteTestNG.java:111)
    at org.testng.remote.RemoteTestNG.initAndRun(RemoteTestNG.java:204)
    at org.testng.remote.RemoteTestNG.main(RemoteTestNG.java:175)

FAILED: allValidData
java.lang.NoClassDefFoundError: Could not initialize class com.demo.singleton.SingletonUsingEnum
    at com.demo.singleton.SingletonUsingEnumTest.allValidData(SingletonUsingEnumTest.java:44)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.testng.internal.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:84)
    at org.testng.internal.MethodInvocationHelper$1.runTestMethod(MethodInvocationHelper.java:200)
    at org.springframework.test.context.testng.AbstractTestNGSpringContextTests.run(AbstractTestNGSpringContextTests.java:157)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.testng.internal.MethodInvocationHelper.invokeHookable(MethodInvocationHelper.java:212)
    at org.testng.internal.Invoker.invokeMethod(Invoker.java:707)
    at org.testng.internal.Invoker.invokeTestMethod(Invoker.java:901)
    at org.testng.internal.Invoker.invokeTestMethods(Invoker.java:1231)
    at org.testng.internal.TestMethodWorker.invokeTestMethods(TestMethodWorker.java:127)
    at org.testng.internal.TestMethodWorker.run(TestMethodWorker.java:111)
    at org.testng.TestRunner.privateRun(TestRunner.java:767)
    at org.testng.TestRunner.run(TestRunner.java:617)
    at org.testng.SuiteRunner.runTest(SuiteRunner.java:334)
    at org.testng.SuiteRunner.runSequentially(SuiteRunner.java:329)
    at org.testng.SuiteRunner.privateRun(SuiteRunner.java:291)
    at org.testng.SuiteRunner.run(SuiteRunner.java:240)
    at org.testng.SuiteRunnerWorker.runSuite(SuiteRunnerWorker.java:52)
    at org.testng.SuiteRunnerWorker.run(SuiteRunnerWorker.java:86)
    at org.testng.TestNG.runSuitesSequentially(TestNG.java:1224)
    at org.testng.TestNG.runSuitesLocally(TestNG.java:1149)
    at org.testng.TestNG.run(TestNG.java:1057)
    at org.testng.remote.RemoteTestNG.run(RemoteTestNG.java:111)
    at org.testng.remote.RemoteTestNG.initAndRun(RemoteTestNG.java:204)
    at org.testng.remote.RemoteTestNG.main(RemoteTestNG.java:175)


===============================================
    Default test
    Tests run: 3, Failures: 2, Skips: 0
===============================================


===============================================
Default suite
Total tests run: 3, Failures: 2, Skips: 0
===============================================

[TestNG] Time taken by org.testng.reporters.JUnitReportReporter@6997f7f4: 8 ms
[TestNG] Time taken by org.testng.reporters.XMLReporter@4474c7fe: 14 ms
[TestNG] Time taken by [FailedReporter passed=0 failed=0 skipped=0]: 6 ms
[TestNG] Time taken by org.testng.reporters.SuiteHTMLReporter@395e7bc4: 14 ms
[TestNG] Time taken by org.testng.reporters.EmailableReporter2@71419cf7: 5 ms
[TestNG] Time taken by org.testng.reporters.jq.Main@6015eb5a: 31 ms

感谢有人能帮我解释发生了什么。

谢谢，NN

通过Enum对Singleton进行单元测试会抛出java.lang.NoClassDefFoundError

2 个答案: