I am reading Cristopher Alexander's Notes on the Synthesis of Form, and he is describing a solution to a problem as having good fit, when there is an absence of bad fit; we can't describe all of the qualities of good fit because it's too complex, but we can identify the bad qualities that stick out.The complexity of software means that we can't understand all the possible relationships - the qualities of good fit, but we can identify when code isn't doing what it's supposed to - the bad fit.I'm wondering then, is the purpose of unit tests to identify a bad fit in the solution? 
Unit Testing and Fit
unit testing;testing