junitテストで発生した問題:java.lang.NoClassDefFoundError: org/hamcrest/SelfDescribing

に質問

今日、コードをテストするときに次のエラーを報告します.

java.lang.NoClassDefFoundError: org/hamcrest/SelfDescribing

	at java.lang.ClassLoader.defineClass1(Native Method)
	at java.lang.ClassLoader.defineClass(ClassLoader.java:763)
	at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
	at java.net.URLClassLoader.defineClass(URLClassLoader.java:467)
	at java.net.URLClassLoader.access$100(URLClassLoader.java:73)
	at java.net.URLClassLoader$1.run(URLClassLoader.java:368)
	at java.net.URLClassLoader$1.run(URLClassLoader.java:362)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.net.URLClassLoader.findClass(URLClassLoader.java:361)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:335)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
	at org.junit.internal.builders.JUnit4Builder.runnerForClass(JUnit4Builder.java:10)
	at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:59)
	at org.junit.internal.builders.AllDefaultPossibilitiesBuilder.runnerForClass(AllDefaultPossibilitiesBuilder.java:26)
	at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:59)
	at org.junit.internal.requests.ClassRequest.getRunner(ClassRequest.java:26)
	at org.junit.internal.requests.FilterRequest.getRunner(FilterRequest.java:31)
	at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:49)
	at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:33)
	at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:230)
	at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:58)
Caused by: java.lang.ClassNotFoundException: org.hamcrest.SelfDescribing
	at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:335)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
	... 22 more

原因を調査する.

提示によるとクラスSelfDescribingの欠如によるものと思われ、文書をめくるとjunit 4で発見する.11以降のバージョンではhamcrestパッケージは含まれておらず、hamcrest-core.jarパッケージを追加する必要があります. ：

JUnit now uses the latest version of Hamcrest. Thus, you can use all the available matchers and benefit from an improved assertThat which will now print the mismatch description from the matcher when an assertion fails.


junit.jar: Includes the Hamcrest classes. The simple all-in-one solution to get started quickly.`Starting with version 4.11`, Hamcrest is` no longer` included in this jar.

解決する

2つの解決方法:
1、Junitのバージョンを変更せず、hamcrest-coreパッケージを追加する.

 <dependency>
          <groupId>junitgroupId>
          <artifactId>junitartifactId>
          <version>4.12version>
          <scope>testscope>
      dependency>

<dependency>
    <groupId>org.hamcrestgroupId>
    <artifactId>hamcrest-coreartifactId>
    <version>2.2version>
    <scope>testscope>
dependency>

2、低バージョンのJunitに変更

 <dependency>
          <groupId>junitgroupId>
          <artifactId>junitartifactId>
          <version>4.10version>
          <scope>testscope>
 dependency>