def test_precision(self, ratio):
"""zipstance(a, x*a + (1 - x)*b) ~ 1 - x, if zipstance(a, b) ~ 1"""
eps = 0.02
n = 10000
a = ''.join([random.choice(string.ascii_letters + '. ') for _ in range(n)])
b = ''.join([random.choice(string.ascii_letters + '. ') for _ in range(n)])
dist = zipstance(a, a[0:int(ratio*n)] + b[int(ratio*n):])
self.assertTrue(dist >= 1 - ratio - eps)
self.assertTrue(dist <= 1 - ratio + eps)
def test_triangle_inequality(self, a, b, c):
self.assertTrue(zipstance(a, c) <= zipstance(a, b) + zipstance(b, c))
def test_coincidence(self, a, b):
aa = zipstance(a, a)
bb = zipstance(b, b)
ab = zipstance(a, b)
self.assertTrue(aa <= ab)
self.assertTrue(bb <= ab)
def test_symmetry(self, a, b):
eps = 0.02
ab = zipstance(a, b)
ba = zipstance(b, a)
self.assertTrue(ab <= ba + eps)
self.assertTrue(ab >= ba - eps)
def test_positivity(self, a, b):
self.assertTrue(zipstance(a, b) >= 0)