assertEquals pop up error window?

Hi,

I have a groovy step that has following line of code

assertEquals "name: ", "john", "johnn"

When I run the step, I got a pop up window saying

java.lang.AssertionError: name: expected<john[]>but was:<john[n]>

What I need is print the above error message in the log/console instead of a pop up window.

Thanks.