def test_always_mutate(self):
"""Test ability to cause mutations.
"""
mutator = ConversionMutation(mutation_rate=1.0)
# when we mutate randomly by chance, we expect to get 2/3
# visible mutations (there are three letters in the alphabet and
# one change cannot be observed since it is a mutation back to itself)
# For a four letter genome, the chance of being exactly the same
# after mutations is about .01, so being better than 90% different
# if a reasonable expectation.
expected_percent = .9
self._always_mutate(mutator, expected_percent)
def test_never_mutate(self):
"""Make sure we do not mutate at unexpected times.
"""
mutator = ConversionMutation(mutation_rate=0.0)
self._never_mutate(mutator)