BirthME, Doulas

However, the functionality will be duplicated by the AssertJ toolset.With the JDK8, lambdas enter the test scene, and they have proved to be an interesting way to assert exceptional behaviour.

Focus on the new OAuth2 stack in Spring Security 5

The high level overview of all the articles on the site. In this quick tutorial, we'll be looking at how to test if an exception was thrown, using JUnit library.Of course, we'll make sure to cover both the JUnit 4 and JUnit 5 versions. Become a writer on the site, in the Java, Computer Science, Scala, Linux, and Kotlin areas.


This is less verbose than the ExpectedException rule of JUnit 4.7. your coworkers to find and share information. This assert will fail if a) the exception is of the wrong type (eg. If you use java … In fact, one can write a helper method quite simply:Zero dependencies: no need for mockito, no need powermock; and works just fine with final classes.In my case I always get RuntimeException from db, but messages differ. @bln-tom Technically it is two different steps, they're just not in that order.

You … @Airduster one implementation of this idea that's available on Maven is @CristianoFontes a simpler version of this API is slated for JUnit 4.13. if you got a Null Pointer instead) and b) the exception wasn't ever thrown.To solve the same problem I did set up a small project:

In this approach, you need to wrap the act in a first assert to catch it first.That would require more code in every test to do the assertion. There are two advantages here, compared to skaffman's solution.

As Mockito is still not updated These issues won't apply once the library supports lambdas.

在Java中，assert关键字是从JAVA SE 1.4 引入的，为了避免和老版本的Java代码中使用了assert关键字导致错误，Java在执行的时候默认是不启动断言检查的（这个时候，所有的断言语句都 将忽略！），如果要开启断言检查，则需要用开关-enableassertions或-ea来开启。

What is important, is that if I try to retrieve something that isn't there, I get an exception. Just answering (a popular question) for the rep.
... but it is possible to assert that no exception has been thrown.

@ycomp I suspect this name conflict may be by design: the AssertJ library therefore strongly encourages you never to use the JUnit @weston actually I've just used your technique in AssertJ 2.0.0.

I have also discussed the below options in my post IMHO, the best way to check for exceptions in JUnit is the try/catch/fail/assert pattern:The most flexible and elegant answer for Junit 4 I found in the I tried many of the methods here, but they were either complicated or didn't quite meet my requirements. more about assertJ throwby: @ycomp Well it is a new answer on a very old question, so the score difference is deceptive.That's probably the best solution if one can use Java 8 and AssertJ !

Stack Overflow for Teams is a private, secure spot for you and That's more code and would be error-prone.Also, you won't see what kind of Exception ex is in the test results when the day comes where the test fails.This can be improved a bit by changing how you assert at the end.

Note that AssertJ Core 3.x includes all AssertJ Core 2.x features and adds Java 8 specific ones (like exception assertions with lambdas).

By using our site, you acknowledge that you have read and understand our Having code after an expected exception (with the exception of closing resources in a finally) is unhelpful anyway since it should never be executed if the exception is thrown.This is the best approach. Android support. AssertJ has been updated to provide a nice fluent API to assert exceptional behaviour.With a near-complete rewrite of JUnit 5, assertions have been Now that JUnit 5 and JUnit 4.13 have been released, the best option would be to use Here is an example that verifies an exception is thrown, and uses The advantages over the approaches in the other answers are:How about this: catch a very general exception, make sure it makes it out of the catch block, then assert that the class of the exception is what you expect it to be.

Java allows exceptions for flow of control.

I want to test the behaviour of the class. looking for "xyz" in the message "unrecognized code 'xyz'").I think NamshubWriter's approach gives you the best of both worlds.Using ExpectedException you could call N exception.expect per method to test like this exception.expect(IndexOutOfBoundsException.class); foo.doStuff1(); exception.expect(IndexOutOfBoundsException.class); foo.doStuff2(); exception.expect(IndexOutOfBoundsException.class); foo.doStuff3();@user1154664 Actually, you can't. @skaffman This wouldn't work with org.junit.experimental.theories.Theory runned by org.junit.experimental.theories.TheoriesRoy Osherove discourages this kind of Exception testing in I disagree with @Kiview/Roy Osherove. Firstly, the @MJafarMash if the exception you expect to throw is checked, then you would add that exception to the throws clause of the test method.

Personally I continue using the 3rd option even with Junit4 for readability, to avoid empty catch block you can also catch Throwable and assert type of eIs it possible to use ExpectedException to expect checked exception?All it is is an accumulation of the top three answers.