How to write a Data Driven Test in JUnit 4 - Parameterized Unit Test

This video demonstrates converting a JUnit test into a Parameterized data driven test.

In JUnit 4 to create a parameterized test we:

- create a static method to provide the data
- the method providing data should return a collection of object arrays
- we can provide a name attribute for the parameter method which dynamically changes the display name of the test
- our test class needs a constructor to setup the data when called by JUnit Runner
- our test methods do not take parameters but they all use the same data provided by the constructor

An explanatory blog post with links to the source code is here:

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[raulsouto]

Excelent explanation. I wasn't understanding the concept really well, but I was able to get the code from class and relate with your material. Thank you very much!

[nickfast]

That’s a nice video, thank you a lot!

[hm]

Greate explanation, thank you very much!!

[stephenjohnson]

How do we deal with throwing exceptions in this? Say, for example, the expected behavior for the code I am testing is to throw a NullPointerException. How do I add that to my list of test values?