How many times have we heard:

Unit tests provide a sort of safety net which "[allows] you to refactor at any time without fear of breaking existing code, so you can constantly improve the design of your program"

But those of you that are familiar with testing know that this is nothing but a regression test:

A regression test is "a testing technique consisting of the repetition of a test after the work product under test has been iterated. Regression testing is used to identify any defects were inadvertently introduced (i.e., to determine if the work product has regressed) since the previous test."

I cannot honestly say that I have ever heard "safety net" tests called regression tests. Why is this? Are the more aglie methodologies trying to separate themselves from the more heavy-weight methodologies by using a different nomenclature? Are there people out there believing that they've discovered something new?

Send your thoughts!