class TestExpression(unittest.TestCase):
def setUp(self):
self.expression = Expression()
def test_InitialisesWithOneTerm(self):
terms = self.expression.terms
self.assertEqual(len(terms), 1)
def test_MutationCanCreateTerm(self):
cfg.set('Function', 'term_creation_chance', '1.0')
cfg.set('Function', 'term_deletion_chance', '0.0')
pre_count = len(self.expression.terms)
self.expression.mutate()
post_count = len(self.expression.terms)
self.assertEqual(pre_count, post_count - 1)
def test_MutationCanDeleteTerm(self):
cfg.set('Function', 'term_creation_chance', '0.0')
cfg.set('Function', 'term_deletion_chance', '1.0')
self.expression._add_term()
pre_count = len(self.expression.terms)
self.expression.mutate()
post_count = len(self.expression.terms)
self.assertEqual(pre_count, post_count + 1)
def test_ExpressionSummation(self):
class DoublingTerm(object):
def f(self, x):
return 2 * x
terms = 3
x = 1
self.expression.terms = [DoublingTerm() for n in range(3)]
expected = terms * x * 2
self.assertEqual(expected, self.expression.f(x))
def test_ExpressionInfinityBounds(self):
class PositiveInfinityTerm(object):
def f(self, x):
return float('inf')
class NegativeInfinityTerm(object):
def f(self, x):
return -float('inf')
x = 1
self.expression.terms = [PositiveInfinityTerm()]
expected = float_info.max
self.assertEqual(expected, self.expression.f(x))
self.expression.terms = [NegativeInfinityTerm()]
expected = -float_info.max
self.assertEqual(expected, self.expression.f(x))
def setUp(self):
self.expression = Expression()
