blocks|key|2732236|text|测试用例:|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|2732237|public+class+SimpleDateFormatExampleTest+{

++++@SuppressWarnings("deprecation")
++++@Test(expected=ParseException.class)
++++public+void+testConvertStringToDate()+throws+ParseException+{
++++++++SimpleDateFormatExample+simpleDateFormatExample+=+new+SimpleDateFormatExample();

++++Assert.assertNotNull(simpleDateFormatExample.convertStringToDate("08-16-2011"));|code-block|syntax|javascript|2732238|如果不使用(expected=ParseException.class)，下面的内容将通过|CODE|2732239|Assert.assertNotNull(simpleDateFormatExample.convertStringToDate("08/16/2011"));

++++}|2732240|测试类|2732241|public+class+SimpleDateFormatExample+{


++++public+Date+convertStringToDate(String+dateStr)+throws+ParseException{
++++++++return+new+SimpleDateFormat("mm/DD/yyyy").parse(dateStr);
++++}
}|2732242|entityMap^0|0|5|0|0|5|V|0|0|0|3|0|0^^$0|@$1|2|3|4|5|6|7|V|8|@$9|W|A|X|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|Y|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|Z|8|@$9|10|A|11|B|M]]|D|@]|E|$]]|$1|N|3|O|5|H|7|12|8|@]|D|@]|E|$I|J]]|$1|P|3|Q|5|6|7|13|8|@$9|14|A|15|B|C]]|D|@]|E|$]]|$1|R|3|S|5|H|7|16|8|@]|D|@]|E|$I|J]]|$1|T|3|-4|5|6|7|17|8|@]|D|@]|E|$]]]|U|$]]

Test Case :

<pre><code>public class SimpleDateFormatExampleTest {

 @SuppressWarnings("deprecation")
 @Test(expected=ParseException.class)
 public void testConvertStringToDate() throws ParseException {
 SimpleDateFormatExample simpleDateFormatExample = new SimpleDateFormatExample();

 Assert.assertNotNull(simpleDateFormatExample.convertStringToDate("08-16-2011"));
</code></pre>

The following will pass without <code>(expected=ParseException.class)</code>

<pre><code>Assert.assertNotNull(simpleDateFormatExample.convertStringToDate("08/16/2011"));

 }
</code></pre>

Test Class

<pre><code>public class SimpleDateFormatExample {


 public Date convertStringToDate(String dateStr) throws ParseException{
 return new SimpleDateFormat("mm/DD/yyyy").parse(dateStr);
 }
}
</code></pre>

blocks|key|945901|text|在JUnit4中，实现这一目标的正确方法是使用一个带有@Rule注释的ExpectedException公共字段，如下所示：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|945902|import+org.junit.rules.ExpectedException;
import+org.junit.Rule;
import+org.junit.Test;


public+class+MyTestClass+{
++@Rule+
++public+ExpectedException+thrown+=+ExpectedException.none();

++@Test
++public+void+aTestThatSucceedsOnlyIfRuntimeExceptionIsThrown()+{
++++++thrown.expect(RuntimeException.class);++
++++++//+invoke+code+to+be+tested...
++}
}|code-block|syntax|javascript|945903|请注意，您也使用了@Test(expected=RuntimeException.class)，但是通常认为前者更优越，原因如下:它允许您在测试中指定应该抛出异常的确切点。如果使用后者，如果测试中的任何一行都抛出(预期类型的)异常，测试就会成功，这通常不是您想要的。|945904|entityMap|0|LINK|mutability|MUTABLE|url|http://junit.org/javadoc/latest/org/junit/rules/ExpectedException.html^0|R|5|Z|H|0|0|0|9|12|0^^$0|@$1|2|3|4|5|6|7|U|8|@$9|V|A|W|B|C]]|D|@$9|X|A|Y|1|Z]]|E|$]]|$1|F|3|G|5|H|7|10|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|11|8|@$9|12|A|13|B|C]]|D|@]|E|$]]|$1|M|3|-4|5|6|7|14|8|@]|D|@]|E|$]]]|N|$O|$5|P|Q|R|E|$S|T]]]]

The proper way to achieve that, in JUnit4, is to use an <a href="http://junit.org/javadoc/latest/org/junit/rules/ExpectedException.html" rel="nofollow">ExpectedException</a> public field, annotated with <code>@Rule</code>, as follows:

<pre><code>import org.junit.rules.ExpectedException;
import org.junit.Rule;
import org.junit.Test;


public class MyTestClass {
 @Rule 
 public ExpectedException thrown = ExpectedException.none();

 @Test
 public void aTestThatSucceedsOnlyIfRuntimeExceptionIsThrown() {
 thrown.expect(RuntimeException.class); 
 // invoke code to be tested...
 }
}
</code></pre>

Note that you also use <code>@Test(expected=RuntimeException.class)</code> but the former is usually considered superior for the following reason: it allows you to specify the exact point in your test where an exception should be thrown. If you use the latter the test will succeed if any line inside it throws an exception (of the expected type) which is often not what you want.

blocks|key|945906|text|你为什么不能在考试中抓住你的异常呢？有不同的方法可以做到这一点。就像注释@Test(expected+=+DataAccessException.class)一样，这也需要逐个案例的使用。但下面是我的建议。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|945907|public+class+TestCase{
++++@Test
++++public+void+method1_test_expectException+()+{
+++++try{
+++++//+invoke+the+method+under+test...
+++++Assert.fail("Should+have+thrown+an+exception");+
+++++//+This+above+line+would+only+be+reached+if+it+doesnt+throw+an+exception+thus+failing+your+test.+
++++++++++++++++}
+++++catch(<your+expected+exception>+e){
+++++++Assert.assertEquals(e.getcode(),+somce+error+code);
+++++}
+}|code-block|syntax|javascript|945908|使用这种方法有几个好处。|945909|如果您有自定义异常(带有错误代码)，则可以断言错误代码。这样就收紧了你的测试箱。|unordered-list-item|945910|任何其他类型相同但错误代码不同的意外异常都会失败。(当您处于持续开发阶段时，这会有所帮助，并且团队会不断地为更新的需求重构代码。测试捕捉到它。)|945911|entityMap^0|10|17|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|T|8|@$9|U|A|V|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|W|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|X|8|@]|D|@]|E|$]]|$1|M|3|N|5|O|7|Y|8|@]|D|@]|E|$]]|$1|P|3|Q|5|O|7|Z|8|@]|D|@]|E|$]]|$1|R|3|-4|5|6|7|10|8|@]|D|@]|E|$]]]|S|$]]

Why cant you just catch your exception in the test? There are different ways of doing this. Like annotating <code>@Test(expected = DataAccessException.class)</code> and that needs to be used on a case by case basis too. But below way is what i would propose. 

<pre><code>public class TestCase{
 @Test
 public void method1_test_expectException () {
 try{
 // invoke the method under test...
 Assert.fail("Should have thrown an exception"); 
 // This above line would only be reached if it doesnt throw an exception thus failing your test. 
 }
 catch(&lt;your expected exception&gt; e){
 Assert.assertEquals(e.getcode(), somce error code);
 }
 }
</code></pre>

<h2>A couple of benefits using this approach.</h2>

<ul>
<li>If you have your custom exception, with an error code, you can
assert for the error code. Thus tightening your testcase. </li>
<li>Any other unexpected exception of the same type but of a different error
code would fail the test. (This helps when you are in continuous
development and the team keeps refactoring the code for newer
requirements. The test catches it.)</li>
</ul>

Is it possible for that a JUnit test succeeds if it returns the expected exception?

Can you tell me how to implements such test by a simplified example?

Thanks a lot.

JUnit : a Successful test if an exception is catched

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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如果JUnit测试返回预期的异常，它会成功吗？你能告诉我如何通过一个简化的例子来实现这样的测试吗？非常感谢。

问JUnit :一个成功的测试是否捕获了异常
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