Question

我正在为我的用例创建一个新的@Rule，看起来像

public class ActiveDirectoryConfigurationRule extends ExternalResource {

  @Rule
  public TemporaryFolder temporaryFolder = new TemporaryFolder();

  public File addActiveDirectoryConfigurationToFile(ActiveDirectoryConfiguration configuration) throws IOException {
    File file = temporaryFolder.newFile();
    objectMapper.writeValue(file, configuration);
    return file;
  }

  private ObjectMapper registerJdk8ModuleAndGetObjectMapper() {
    ObjectMapper objectMapper = new ObjectMapper();
    objectMapper.registerModule(new Jdk8Module());
    return objectMapper;
  }
}

在我的Test我用它作为

public class ActiveDirectoryConfigurationStoreTest {

      @Rule
      public ActiveDirectoryConfigurationRule configurationRule = new ActiveDirectoryConfigurationRule();

          @Test
          public void getWhenConfigurationExists() throws Exception {
            ActiveDirectoryConfiguration activeDirectoryConfiguration = //....;
            File configurationToFile = configurationRule.addActiveDirectoryConfigurationToFile(activeDirectoryConfiguration);

            ActiveDirectoryConfigurationStore configurationStore = new ActiveDirectoryConfigurationStore(configurationToFile);
            Optional<ActiveDirectoryConfiguration> mayBeConfiguration = configurationStore.getConfiguration();
            assertTrue(mayBeConfiguration.isPresent());
          }
        }

当我运行此测试时，我收到错误

java.lang.IllegalStateException: the temporary folder has not yet been created

    at org.junit.rules.TemporaryFolder.getRoot(TemporaryFolder.java:145)
    at org.junit.rules.TemporaryFolder.newFile(TemporaryFolder.java:78)
    at com.conf.store.ActiveDirectoryConfigurationRule.addActiveDirectoryConfigurationToFile(ActiveDirectoryConfigurationRule.java:48)
    at com.conf.store.ActiveDirectoryConfigurationStoreTest.getWhenConfigurationExists(ActiveDirectoryConfigurationStoreTest.java:25)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
    at org.junit.rules.ExternalResource$1.evaluate(ExternalResource.java:48)
    at org.junit.rules.RunRules.evaluate(RunRules.java:20)
    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
    at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:119)
    at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:42)
    at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:234)
    at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:74)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:144)

似乎在创建自己的@Rule时，我无法依赖任何现有的@Rule

这是问题吗？以及如何解决它？

Answer 1

是的，我不认为JUnit内置了任何东西，让你像你一样“嵌套”@Rule对象。

我认为最明显的选择是：

在您的自定义@Rule中，在适当的时间调用您的孩子@Rule上的各种方法。（基本上，假装你是JUnit库，按照它的界面使用@Rule。）我没有深入研究细节，看它有多复杂。
让@Rule扩展TemporaryFolder而不是ExternalResource，确保在您覆盖的任何方法中调用super()。这可以让你做“一切TemporaryFolder然后做一些”，这可能不是完美的OO理论（因为它不是真正的TemporaryFolder类型），但应该按照你想要的方式工作。我在设置需要为我的测试设置特定环境的特定文件夹时使用了这种方法，并且它运行得相当好。
让您的自定义@Rule作为构造函数参数接受TemporaryFolder引用，然后将其保存在字段中并根据需要使用。这要求您的@Rule的所有用户都包含两个@Rule对象，但是可能会清楚地表明测试确实需要一个临时文件夹来完成它的工作以及您的特定自定义设置。

Answer 2

不支持在规则中使用@Rule声明规则。但您可以手动运行其他规则。

public class ActiveDirectoryConfigurationRule implements TestRule {

  private TemporaryFolder temporaryFolder = new TemporaryFolder();

  @Override
  public Statement apply(Statement base, Description description) {
    Statement testWrappedWithYourCode = new Statement() {
      public void evaluate() {
        before();

        List<Throwable> errors = new ArrayList<Throwable>();
        try {
          base.evaluate();
        } catch (Throwable t) {
          errors.add(t);
        } finally {
          try {
            after();
          } catch (Throwable t) {
            errors.add(t);
          }
        }
        MultipleFailureException.assertEmpty(errors);
      }
    }

    return temporaryFolder.apply(testWrappedWithYourCode, description);
  }

  public File addActiveDirectoryConfigurationToFile(ActiveDirectoryConfiguration configuration) throws IOException {
    File file = temporaryFolder.newFile();
    objectMapper.writeValue(file, configuration);
    return file;
  }

  private ObjectMapper registerJdk8ModuleAndGetObjectMapper() {
    ObjectMapper objectMapper = new ObjectMapper();
    objectMapper.registerModule(new Jdk8Module());
    return objectMapper;
  }
}

java.lang.IllegalStateException：尚未创建临时文件夹

2 个答案: