我們做單元測試NUnit中,有一個斷言Assert.Throws很好用,現在我們來擴展一下也實現類似成功能,大家參考使用吧
我們做單元測試NUnit中,有一個斷言Assert.Throws很好用,但當我們使用MsTest時你需要這樣寫: 代碼如下: [TestMethod] [ExpectedException(typeof(ArgumentNullException))] public void WriteToTextFile() { PDFUtility.WriteToTextFile("D:ACA.pdf", null); } 現在讓我們來擴展一下也實現類似成功能,增加一個類,代碼如下: 代碼如下: /// <summary> /// Useful assertions for actions that are expected to throw an exception. /// </summary> public static class ExceptionAssert { /// <summary> /// Executes an exception, expecting an exception to be thrown. /// Like Assert.Throws in NUnit. /// </summary> /// <param name="action">The action to execute</param> /// <returns>The exception thrown by the action</returns> public static Exception Throws(Action action) { return Throws(action, null); } /// <summary> /// Executes an exception, expecting an exception to be thrown. /// Like Assert.Throws in NUnit. /// </summary> /// <param name="action">The action to execute</param> /// <param name="message">The error message if the expected exception is not thrown</param> /// <returns>The exception thrown by the action</returns> public static Exception Throws(Action action, string message) { try { action(); } catch (Exception ex) { // The action method has thrown the expected exception. // Return the exception, in case the unit test wants to perform further assertions on it. return ex; } // If we end up here, the expected exception was not thrown. Fail! throw new AssertFailedException(message ?? "Expected exception was not thrown."); } /// <summary> /// Executes an exception, expecting an exception of a specific type to be thrown. /// Like Assert.Throws in NUnit. /// </summary> /// <param name="action">The action to execute</param> /// <returns>The exception thrown by the action</returns> public static T Throws<T>(Action action) where T : Exception { return Throws<T>(action, null); } /// <summary> /// Executes an exception, expecting an exception of a specific type to be thrown. /// Like Assert.Throws in NUnit. /// </summary> /// <param name="action">The action to execute</param> /// <param name="message">The error message if the expected exception is not thrown</param> /// <returns>The exception thrown by the action</returns> public static T Throws<T>(Action action, string message) where T : Exception { try { action(); } catch (Exception ex) { T actual = ex as T; if (actual == null) { throw new AssertFailedException(message ?? String.Format("Expected exception of type {0} not thrown. Actual exception type was {1}.", typeof(T), ex.GetType())); } // The action method has thrown the expected exception of type 'T'. // Return the exception, in case the unit test wants to perform further assertions on it. return actual; } // If we end up here, the expected exception of type 'T' was not thrown. Fail! throw new AssertFailedException(message ?? String.Format("Expected exception of type {0} not thrown.", typeof(T))); } } 好了,現在我們在MsTest中可以這樣了,看下面代碼: 代碼如下: [TestMethod] public void WriteToTextFile2() { //Implement Assert.Throws in MSTest ExceptionAssert.Throws<ArgumentNullException>(()=> PDFUtility.WriteToTextFile("D:ACA.pdf", null) ,"Output file path should not be null"); }
