def setUp(self):
unittest.TestCase.setUp(self)
self.g = DNAHistoryGraph()
self.s1 = self.g.newSegment()
self.s2 = self.g.newSegment("A")
self.s3 = self.g.newSegment("T")
self.s4 = self.g.newSegment("A")
self.g.createBranch(self.s1, self.s2)
self.g.createBranch(self.s1, self.s3)
self.g.createBranch(self.s1, self.s4)
