Code duplication is a common problem for developers. It's easy to copy and paste code around your application, but you're asking for trouble. Unfortunately, this kind of problem also extends to unit tests. In this new post to his site James Fuller looks at one way to help with this - using the @dataProvider to limit the repetitive data sets across tests.

PHPUnit offers a handy annotation called @dataProvider which can be used for all sorts of handy testing situations. Typically you will use this to feed in a wide variety of data into the same test to ensure that the system-under-test can handle a variety of inputs. Over time I have discovered a few other neat uses for dataProvider methods that I want to share with you today.

He provides some code samples showing how to use the dataProvider in a few tests, setting up an "allowed word" example. He gets a bit more complex with another test that takes in multiple parameters to "mix colors". In his last example he shows a data provider that converts names from camelCase to user_scores.