TestNG – 預期異常和預期消息教程 · HowToDoInJava 中文系列教程

# TestNG – 預期異常和預期消息教程 > 原文： [https://howtodoinjava.com/testng/testng-expected-exception-and-expected-message-tutorial/](https://howtodoinjava.com/testng/testng-expected-exception-and-expected-message-tutorial/) 在編寫單元測試時，在某些情況下，我們需要驗證在執行過程中程序是否引發了異常。通過允許用戶**指定在執行過程中測試方法**引發的異常類型，TestNG 提供了一種測試此類情況的功能。它支持為驗證提供多個值。如果測試引發的異常不屬于用戶輸入列表，則測試方法將標記為失敗。讓我們創建一個示例測試，并了解異常測試如何在 TestNG 中工作。 ```java @Test ( expectedExceptions = { IOException.class, NullPointerException.class } ) ``` 讓我們看一個例子，以更好地理解它。 ## 預期異常測試示例在下面的測試中，我們有兩種測試方法，即`exceptionTestOne()`和`exceptionTestTwo()`。這里`exceptionTestOne()`拋出`IOException`，而`exceptionTestTwo()`拋出`Exception`。在使用`Test`注解時，使用`ExpectedExceptions`屬性值提到了在運行這些測試時驗證的預期異常。 ```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(); } } ``` 以上測試運行的輸出如下： ```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 =============================================== ``` 從測試結果中可以看出，`exceptionTestTwo()`在執行期間被 TestNG 標記為失敗。測試失敗，因為所述方法引發的異常與`ExpectedExceptions`列表中提供的異常列表不匹配。 ## 帶有驗證消息的預期異常測試的示例您還可以根據測試引發的異常消息來驗證測試。正則表達式也可以用于驗證錯誤消息，可以使用`.*.`完成此操作，具體取決于正則表達式的位置，我們可以在驗證異常消息時使用它進行模式匹配，例如開始，包含，結束于。讓我們學習如何根據拋出的異常消息編寫異常測試。 ```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"); } } ``` 以上測試運行的輸出如下： ```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 =============================================== ``` 在上述測試方法中，`exceptionTestThree()`失敗，因為預期的消息不匹配。 **祝您學習愉快！**