Percentage matching of text

[Bruce Eckel]

Background: for the 4th edition of Thinking in Java, I'm trying to
once again improve the testing scheme for the examples in the book. I
want to verify that the output I show in the book is "reasonably
correct." I say "Reasonably" because a number of examples produce
random numbers or text or the time of day or in general things that do
not repeat themselves from one execution to the next. So, much of the
text will be the same between the "control sample" and the "test
sample," but some of it will be different.

I will be using Python or Jython for the test framework.

What I'd like to do is find an algorithm that produces the results of
a text comparison as a percentage-match. Thus I would be able to
assert that my test samples must match the control sample by at least
(for example) 83% for the test to pass. Clearly, this wouldn't be a
perfect test but it would help flag problems, which is primarily what
I need.

Does anyone know of an algorithm or library that would do this? Thanks
in advance.

Bruce Eckel
Bruce at EckelObjects.com