A simple heuristic for when you get stuck

James Bach gave me a sample application to test. It was a simple application with what turned out to be a fairly straightforward bug in it. After a few minutes of testing I started to have a really hard time coming up with new test cases to try. I was stuck.

James offered the following heuristic:

1. Look over the test cases you have already executed.


2. Find a pattern.


3. In the next test case, violate that pattern.

It worked. I found the bug on the very next test case.

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Previous Comments

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>>>>>Creativity techniques, for heuristics

Submitted by Mitch Goldman on Fri, 29/07/2005 - 07:36.

I've found this page to be useful:
http://www.mycoted.com/creativity/techniques/

It's got links to lots of idea-generating techniques.

>>>>>Too much boundary testing

Submitted by Mike Kelly on Thu, 28/07/2005 - 10:19.

The application was an IP Address syntax checker. Almost all of my test cases were test cases at the numeric boundaries (0 and 255), reserved boundaries (10.0.0.0 through 10.255.255.255; 172.16.0.0 through 172.31.255.255; and 192.168.0.0 through 192.168.255.255), and using real IP Addresses (like the IP Address for the computer I was testing on). When I looked at the tests I had run, I found that I hadn't really been using all the digits available to me. I tried a random test case with various values I had not used and I stumbled across the bug.

>>>>>what was the pattern

Submitted by jayrod84 on Thu, 28/07/2005 - 06:30.

Could you maybe explain the pattern that you violated?