class DisjointSetTest(unittest.TestCase):
def setUp(self):
self.ds = DisjointSet()
@istest
def add_elements(self):
self.ds.add(1)
self.assertEquals(1, len(self.ds))
self.ds.add('a')
self.assertEquals(2, len(self.ds))
@istest
def add_many_elements(self):
self.ds.add_many([1, 2, 3])
self.assertEquals(3, len(self.ds))
self.ds.add_many(letter for letter in 'abc')
self.assertEquals(6, len(self.ds))
@istest
def island_elements_find_themselves(self):
test_elements = [1, 2, 3]
self.ds.add_many(test_elements)
for element in test_elements:
self.assertEquals(element, self.ds.find(element))
@istest
def union_two_elements(self):
elements = [1, 2]
self.ds.add_many(elements)
self.ds.union(1, 2)
self.assert_all_elements_unioned(elements)
@istest
def add_elements_after_a_union(self):
elements = [1, 2, 3]
self.ds.add_many(elements[:2])
self.ds.union(1, 2)
self.ds.add(elements[2])
self.assertEquals(self.ds.find(1), self.ds.find(2))
self.assertEquals(3, self.ds.find(3))
self.assertNotEqual(self.ds.find(2), self.ds.find(3))
self.ds.union(1, 3)
self.assert_all_elements_unioned(elements)
@istest
def transitive_union(self):
elements = [1, 2, 3]
self.ds.add_many(elements)
self.ds.union(1, 2)
self.ds.union(2, 3)
self.assert_all_elements_unioned(elements)
@istest
def union_order_doesnt_matter(self):
elements = [1, 2, 3]
self.ds.add_many(elements)
self.ds.union(1, 2)
self.ds.union(3, 2)
self.assert_all_elements_unioned(elements)
@istest
def multistep_unions(self):
elements = [1, 2, 3, 4, 5, 6]
self.ds.add_many(elements)
self.ds.union(1, 2)
self.ds.union(3, 2)
self.ds.union(5, 4)
self.assertNotEqual(self.ds.find(2), self.ds.find(4))
self.ds.union(4, 3)
self.assertEqual(self.ds.find(2), self.ds.find(4))
self.assertNotEqual(self.ds.find(6), self.ds.find(4))
self.ds.union(6, 2)
self.assert_all_elements_unioned(elements)
@istest
def unioning_joint_elements_has_no_effect(self):
elements = [1, 2, 3, 4]
self.ds.add_many(elements)
self.ds.union(1, 2)
self.ds.union(3, 4)
self.ds.union(2, 3)
self.ds.union(1, 4)
self.assert_all_elements_unioned(elements)
def assert_all_elements_unioned(self, elements):
for a in elements:
for b in elements:
self.assertEquals(self.ds.find(a), self.ds.find(b))
def setUp(self):
self.ds = DisjointSet()
