TestNG – 预期异常和预期消息教程 · HowToDoInJava 中文系列教程

# TestNG – 预期异常和预期消息教程 > 原文： [https://howtodoinjava.com/testng/testng-expected-exception-and-expected-message-tutorial/](https://howtodoinjava.com/testng/testng-expected-exception-and-expected-message-tutorial/) 在编写单元测试时，在某些情况下，我们需要验证在执行过程中程序是否引发了异常。通过允许用户**指定在执行过程中测试方法**引发的异常类型，TestNG 提供了一种测试此类情况的功能。它支持为验证提供多个值。如果测试引发的异常不属于用户输入列表，则测试方法将标记为失败。让我们创建一个示例测试，并了解异常测试如何在 TestNG 中工作。 ```java @Test ( expectedExceptions = { IOException.class, NullPointerException.class } ) ``` 让我们看一个例子，以更好地理解它。 ## 预期异常测试示例在下面的测试中，我们有两种测试方法，即`exceptionTestOne()`和`exceptionTestTwo()`。这里`exceptionTestOne()`抛出`IOException`，而`exceptionTestTwo()`抛出`Exception`。在使用`Test`注解时，使用`ExpectedExceptions`属性值提到了在运行这些测试时验证的预期异常。 ```java public class ExceptionTestDemo { @Test(expectedExceptions = { IOException.class }) public void exceptionTestOne() throws Exception { throw new IOException(); } @Test(expectedExceptions = { IOException.class, NullPointerException.class }) public void exceptionTestTwo() throws Exception { throw new Exception(); } } ``` 以上测试运行的输出如下： ```java [TestNG] Running: C:\Users\somepath\testng-customsuite.xml PASSED: exceptionTestOne FAILED: exceptionTestTwo org.testng.TestException: Expected exception java.io.IOException but got org.testng.TestException: Expected exception java.io.IOException but got java.lang.Exception at org.testng.internal.Invoker.handleInvocationResults(Invoker.java:1497) at org.testng.internal.Invoker.invokeTestMethods(Invoker.java:1245) 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) Caused by: org.testng.TestException: Expected exception java.io.IOException but got java.lang.Exception at org.testng.internal.Invoker.handleInvocationResults(Invoker.java:1497) at org.testng.internal.Invoker.invokeMethod(Invoker.java:754) at org.testng.internal.Invoker.invokeTestMethod(Invoker.java:901) at org.testng.internal.Invoker.invokeTestMethods(Invoker.java:1231) ... 16 more Caused by: java.lang.Exception at com.howtodoinjava.test.ExceptionTestDemo.exceptionTestTwo(ExceptionTestDemo.java:16) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.testng.internal.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:84) at org.testng.internal.Invoker.invokeMethod(Invoker.java:714) ... 18 more =============================================== Default test Tests run: 2, Failures: 1, Skips: 0 =============================================== ``` 从测试结果中可以看出，`exceptionTestTwo()`在执行期间被 TestNG 标记为失败。测试失败，因为所述方法引发的异常与`ExpectedExceptions`列表中提供的异常列表不匹配。 ## 带有验证消息的预期异常测试的示例您还可以根据测试引发的异常消息来验证测试。正则表达式也可以用于验证错误消息，可以使用`.*.`完成此操作，具体取决于正则表达式的位置，我们可以在验证异常消息时使用它进行模式匹配，例如开始，包含，结束于。让我们学习如何根据抛出的异常消息编写异常测试。 ```java public class ExceptionTestDemo { @Test(expectedExceptions = { IOException.class }, expectedExceptionsMessageRegExp = "Pass Message test") public void exceptionTestOne() throws Exception { throw new IOException("Pass Message test"); } @Test(expectedExceptions = { IOException.class }, expectedExceptionsMessageRegExp = ".* Message .*") public void exceptionTestTwo() throws Exception { throw new IOException("Pass Message test"); } @Test(expectedExceptions = { IOException.class }, expectedExceptionsMessageRegExp = "Pass Message test") public void exceptionTestThree() throws Exception { throw new IOException("Fail Message test"); } } ``` 以上测试运行的输出如下： ```java [TestNG] Running: C:\Users\somepath\testng-customsuite.xml PASSED: exceptionTestOne PASSED: exceptionTestTwo FAILED: exceptionTestThree org.testng.TestException: Expected exception java.io.IOException but got org.testng.TestException: The exception was thrown with the wrong message: expected "Pass Message test" but got "Fail Message test" at org.testng.internal.Invoker.handleInvocationResults(Invoker.java:1497) at org.testng.internal.Invoker.invokeTestMethods(Invoker.java:1245) 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) Caused by: org.testng.TestException: The exception was thrown with the wrong message: expected "Pass Message test" but got "Fail Message test" at org.testng.internal.Invoker.handleInvocationResults(Invoker.java:1481) at org.testng.internal.Invoker.invokeMethod(Invoker.java:754) at org.testng.internal.Invoker.invokeTestMethod(Invoker.java:901) at org.testng.internal.Invoker.invokeTestMethods(Invoker.java:1231) ... 16 more Caused by: java.io.IOException: Fail Message test at com.howtodoinjava.test.ExceptionTestDemo.exceptionTestThree(ExceptionTestDemo.java:21) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.testng.internal.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:84) at org.testng.internal.Invoker.invokeMethod(Invoker.java:714) ... 18 more =============================================== Default test Tests run: 3, Failures: 1, Skips: 0 =============================================== ``` 在上述测试方法中，`exceptionTestThree()`失败，因为预期的消息不匹配。 **祝您学习愉快！**