def testZeroLength(self):
"""
The function should raise when given an empty string
"""
error = 'Empty original string passed.'
with six.assertRaisesRegex(self, ValueError, error):
mutateString('', 1)
def testZeroLength(self):
"""
The function should raise when given an empty string
"""
error = 'Empty original string passed.'
with six.assertRaisesRegex(self, ValueError, error):
mutateString('', 1)
def testReplacementLengthOneAppearsInOriginal(self):
"""
The function should raise when given a replacement string that contains
just one letter if that letter also appears in the original.
"""
error = 'Impossible replacement'
with six.assertRaisesRegex(self, ValueError, error):
mutateString('x', 1, 'x')
def testDuplicateReplacementLetter(self):
"""
The function should raise when given a replacement string that contains
a duplicate letter.
"""
error = 'Replacement string contains duplicates'
with six.assertRaisesRegex(self, ValueError, error):
mutateString('x', 1, 'aa')
def testTooManyMutationsRequested(self):
"""
The function should raise when asked to perform more mutations than
there are in the original string.
"""
error = 'Cannot make 2 mutations in a string of length 1'
with six.assertRaisesRegex(self, ValueError, error):
mutateString('x', 2)
def testReplacementLengthOneAppearsInOriginal(self):
"""
The function should raise when given a replacement string that contains
just one letter if that letter also appears in the original.
"""
error = 'Impossible replacement'
with six.assertRaisesRegex(self, ValueError, error):
mutateString('x', 1, 'x')
def testDuplicateReplacementLetter(self):
"""
The function should raise when given a replacement string that contains
a duplicate letter.
"""
error = 'Replacement string contains duplicates'
with six.assertRaisesRegex(self, ValueError, error):
mutateString('x', 1, 'aa')
def testTooManyMutationsRequested(self):
"""
The function should raise when asked to perform more mutations than
there are in the original string.
"""
error = 'Cannot make 2 mutations in a string of length 1'
with six.assertRaisesRegex(self, ValueError, error):
mutateString('x', 2)
def testOneReplacement(self):
"""
The function should return all possible correct results (and only those
results) when one mutation is requested and two outcomes are possible.
NOTE: this test is a bit bad because it's non-deterministic.
"""
possible = set(['ab', 'ba'])
seen = set()
for _ in range(100):
result = mutateString('aa', 1, 'ab')
self.assertTrue(result in possible)
seen.add(result)
self.assertEqual(seen, possible)
def testOneReplacement(self):
"""
The function should return all possible correct results (and only those
results) when one mutation is requested and two outcomes are possible.
NOTE: this test is a bit bad because it's non-deterministic.
"""
possible = set(['ab', 'ba'])
seen = set()
for _ in range(100):
result = mutateString('aa', 1, 'ab')
self.assertTrue(result in possible)
seen.add(result)
self.assertEqual(seen, possible)
def testOneDeterministicReplacement(self):
"""
The function should return the correct result when one mutation is
requested and only one mutation is possible.
"""
self.assertEqual('c', mutateString('a', 1, 'ac'))
def testZeroReplacements(self):
"""
The function should return the original string when zero mutations
are requested.
"""
self.assertEqual('acgt', mutateString('acgt', 0, 'x'))
def testFiveDeterminsticReplacements(self):
"""
The function should return the correct result when five mutations are
requested and only one outcome is possible.
"""
self.assertEqual('ccccc', mutateString('aaaaa', 5, 'ac'))
def testFiveDeterminsticReplacements(self):
"""
The function should return the correct result when five mutations are
requested and only one outcome is possible.
"""
self.assertEqual('ccccc', mutateString('aaaaa', 5, 'ac'))
def testOneDeterministicReplacement(self):
"""
The function should return the correct result when one mutation is
requested and only one mutation is possible.
"""
self.assertEqual('c', mutateString('a', 1, 'ac'))
def testZeroReplacements(self):
"""
The function should return the original string when zero mutations
are requested.
"""
self.assertEqual('acgt', mutateString('acgt', 0, 'x'))