Friday, 18 May 2012

Testing multiple properties with single assertion

Every time I was trying to test an object's properties I was neither satisfied writing very verbose tests nor in using some of the out of the box hamcrest matchers. Although using the matchers was a big help, I never managed to make them read the way I wanted.

Another thing that was very important to me, I wanted to have a single assertion per method and a very descriptive description if the test did not pass.

I've decided to write my own matcher and hopefully it will be useful to other people. So, that's what I've done:


Hamcrest matcher to match multiple attributes of an object within a single assertion.

How to use it

NOTE: Make sure you are using org.hamcrest.MatcherAssert.assertThat instead of the JUnit one.

If you run this test, you will get a message like

Now, change the age check to
   property("age", greaterThan(60)) 
And you should get:

Testing object graphs

You can also do this

I use a combination of two matchers to do that:
- BeanMatcher: Provides the "has" method responsible to group all the property matchers.
- BeanPropertyMatcher: Provides the "property" method.

I expect to make more changes to them, so for the most up-to-date version, please check BeanMatcher on my github account.



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