def testSubstApply(self):
"""
Check application of substitutions
"""
self.assertEqual(terms.term2String(self.sigma1(self.t1)), "f(a,g(a))")
self.assertTrue(terms.termEqual(self.sigma1(self.t1), self.t4))
self.assertTrue(terms.termEqual(self.sigma2(self.t1), self.t5))
def testSubstBasic(self):
"""
Test basic stuff.
"""
tau = self.sigma1.copy()
self.assertTrue(terms.termEqual(tau("X"), self.sigma1("X")))
self.assertTrue(terms.termEqual(tau("Y"), self.sigma1("Y")))
self.assertTrue(terms.termEqual(tau("Z"), self.sigma1("Z")))
t = tau.modifyBinding(("X", self.t1))
self.assertTrue(terms.termEqual(t, self.t2))
t = tau.modifyBinding(("U", self.t1))
self.assertEqual(t, None)
self.assertTrue(tau.isBound("U"))
self.assertTrue(terms.termEqual(tau.value("U"), self.t1))
t = tau.modifyBinding(("U", None))
self.assertTrue(not tau.isBound("U"))