Step 3: Break the functionality by slightly mutating it.
Step 3: Break the functionality by slightly mutating it.

Make very small change to the functionality, that you have just created test
for, that you believe will break the test.

If test does not fail, that could mean 2 things:
- understanding of the functionality under the test is not precise;
- you found bug in the functionality, collaborator object(s) or in the test;
- it needs an additional test.

Figure out why test does not fail and make sure it does. Adjust test for the
new understanding or create more tests if necessary. Fix discovered bugs.

waterlink/lemon,waterlink/lemon