Assertionfailederror null in java

AssertionFailedError: null on boolean method Ask Question. Asked 8 years, 7 months ago. Active 8 years, 7 months ago. Viewed 11k times. Improve this question. AnthonyW AnthonyW 1, 4 4 gold badges 24 24 silver badges 46 46 bronze badges.

The error you see is normal if the method foo return false. That means that it should probably not throw a NPE as your expect. By the way, you are using JUnit 4 because of the annotation Test but you still use the the old JUnit 3 Assert class of package junit.

I think you did not encounter a nullpointer inside, you can test this by running the method outside of the asserTrue. Let me know the result. The null is the message you didn't give to the assertTrue method. What is the difference? Show 6 more comments. Active Oldest Votes. Example: JUnit 3: assertTrue false has the same stack trace as assertTrue "null", false JUnit 4: assertTrue false has the same stack trace as assertTrue "", false. If we get to execute the last statement in the thread as planned — all is well, no assertions were violated, if not — something has gone wrong.

And in the case of a fail we rely on the test runner to print out the exception. Generally speaking, I have not found a nice way to assert fine detail inside a thread. The exceptions are cut off from the main thread and therefore never reach the runner. So the only way to look at these tests is to test the side effects after the test is complete or in the middle of the execution, if you can stop your threads reliably.

Hi, I see that you address the same issue I wrote about : I did find a solution that I believe it is reasonable and generic. Why not just check if the threadsCompleted is 1? See code below :. True, but 2 threads are always more interesting. In most cases, where one will use this idea, there will be more than 1 thread :.

You might check out the ConcurrentUnit library as well, which was created for testing these sort of scenarios. You are commenting using your WordPress. You are commenting using your Google account.

You are commenting using your Twitter account. You are commenting using your Facebook account. Notify me of new comments via email. In such case we can pass the error message as the last parameter in a lambda expression:.

The error message in the example is not that complex. However, using this approach JUnit 5 will only construct the error message when the assertion fails. This way, we only pay the cost if failure happens. When running tests, test execution will stop at the first assertion failure.

Using JUnit 5 grouped assertions, we can run all the assertions before reporting a failure. We can do this by using the assertAll method and providing the different assertions as parameters to the method.

This means that we need to assert that both the first and last name are correct:. The first parameter of the assertAll method is an optional title message that identifies the asserted state. If this example were to fail, both assertions be execute before failing the test and reporting the failures together:.

While the JUnit 5 assertions are sufficient for many testing scenarios, sometimes we need more powerful options. For example, maybe we want to make sure a list has a certain size. Or maybe we need to know if the list contains an item with a specific field value. Or maybe we would like to verify that a list is sorted and has exact items in it We could write some logic ourselves, but it would be better if the assertion library would do this for us.

Here JUnit 5 assertions fall short. Therefore, the JUnit 5 documentation recommends using third-party assertion libraries in such cases. The most popular ones are Hamcrest, AssertJ, and Truth. We are not going to all details about these libraries in this tutorial.

Hamcrest is the oldest one of the bunch. In the following example, we want to make sure a list has just one item. We could write this with JUnit 5 assertions:. We can write assertions by passing the assertion method a matcher method as an argument:. Reading out the assertion, this is more fluent and closer to natural language.

However, we could argue that the first example is readable enough, so maybe we are not convinced yet. The main difference between Hamcrest and AssertJ is that Hacmrest relies on matcher methods, while in AssertJ we can chain the method calls.

What if we want to know if a list contains an item with a specific field value? We also removed logic from the test code, which can be prone to errors.

Truth is very similar to AssertJ. The most significant difference is that Truth tries to provide a more straightforward API, while AssertJ has a more comprehensive set of assertions. We want to verify that a list is sorted and has exact items in it This is how it would look like using Truth:. The example code for this guide can be found in GitHub. A software professional seeking for continuous improvement.

Obsessed with test automation and sustainable development. Arho Huttunen. Light Dark Automatic. Overview In this article, we will learn how to verify test results using JUnit 5 assertions.