Added a few knuth-bendix tests (#25)

* added a few knuth-bendix tests

* fixed linting

* Fix linting

Co-authored-by: James D. Mitchell <jdm3@st-andrews.ac.uk>

Author: mariatsalakou

tests/test_knuth_bendix.py

@@ -62,6 +62,106 @@ def test_attributes(self):
     def test_operators(self):
         check_operators(self, KnuthBendix)
 
+    # Tests from libsemigroups
+    def test_006(self):
+        kb = KnuthBendix()
+        kb.set_alphabet("ab")
+        kb.add_rule("aa", "")
+        kb.add_rule("bbb", "")
+        kb.add_rule("ababab", "")
+        self.assertFalse(kb.confluent())
+        kb.run()
+        self.assertEqual(kb.size(), 12)
+        self.assertTrue(kb.confluent())
+
+    def test_009(self):
+        kb = KnuthBendix()
+        kb.set_alphabet("012")
+        kb.add_rule("000", "2")
+        kb.add_rule("111", "2")
+        kb.add_rule("010101", "2")
+        kb.set_identity("2")
+        self.assertEqual(kb.alphabet(), "012")
+        self.assertFalse(kb.confluent())
+        kb.run()
+        self.assertTrue(kb.confluent())
+        self.assertEqual(kb.number_of_active_rules(), 9)
+        ad = kb.gilman_digraph()
+        self.assertEqual(ad.number_of_nodes(), 9)
+        self.assertEqual(ad.number_of_edges(), 13)
+
+    def test_022(self):
+        kb = KnuthBendix()
+        kb.set_alphabet("aAbBcC")
+        kb.set_identity("")
+        kb.set_inverses("AaBbCc")
+        kb.add_rule("Aba", "bb")
+        kb.add_rule("Bcb", "cc")
+        kb.add_rule("Cac", "aa")
+        self.assertFalse(kb.confluent())
+        kb.run()
+        self.assertTrue(kb.confluent())
+        self.assertTrue(kb.equal_to("Aba", "bb"))
+        self.assertTrue(kb.equal_to("Bcb", "cc"))
+        self.assertTrue(kb.equal_to("Cac", "aa"))
+        self.assertEqual(kb.size(), 1)
+
+    def test_024(self):
+        kb = KnuthBendix()
+        kb.set_alphabet("abAB")
+        kb.set_identity("")
+        kb.set_inverses("ABab")
+        kb.add_rule("aaa", "")
+        kb.add_rule("bbb", "")
+        kb.add_rule("abababab", "")
+        kb.add_rule("aBaBaBaBaB", "")
+        self.assertFalse(kb.confluent())
+        kb.run()
+        self.assertTrue(kb.confluent())
+        self.assertEqual(kb.number_of_active_rules(), 183)
+        self.assertTrue(kb.equal_to("aaa", ""))
+        self.assertTrue(kb.equal_to("bbb", ""))
+        self.assertTrue(kb.equal_to("BaBaBaBaB", "aa"))
+        self.assertTrue(kb.equal_to("bababa", "aabb"))
+        self.assertTrue(kb.equal_to("ababab", "bbaa"))
+        self.assertTrue(kb.equal_to("aabbaa", "babab"))
+        self.assertTrue(kb.equal_to("bbaabb", "ababa"))
+        self.assertTrue(kb.equal_to("bababbabab", "aabbabbaa"))
+        self.assertTrue(kb.equal_to("ababaababa", "bbaabaabb"))
+        self.assertTrue(kb.equal_to("bababbabaababa", "aabbabbaabaabb"))
+        self.assertTrue(kb.equal_to("bbaabaabbabbaa", "ababaababbabab"))
+
+    def test_025(self):
+        kb = KnuthBendix()
+        kb.set_alphabet("aAbB")
+        kb.set_identity("")
+        kb.set_inverses("AaBb")
+        self.assertTrue(kb.confluent())
+        kb.run()
+        self.assertTrue(kb.confluent())
+        self.assertTrue(kb.is_obviously_infinite())
+
+    def test_027(self):
+        kb = KnuthBendix()
+        kb.set_alphabet("abB")
+        kb.add_rule("bb", "B")
+        kb.add_rule("BaB", "aba")
+        self.assertFalse(kb.confluent())
+        kb.run()
+        self.assertTrue(kb.confluent())
+        self.assertEqual(kb.number_of_active_rules(), 6)
+        self.assertEqual(
+            kb.active_rules(),
+            [
+                ("Bb", "bB"),
+                ("bb", "B"),
+                ("BaB", "aba"),
+                ("BabB", "abab"),
+                ("Baaba", "abaaB"),
+                ("Bababa", "ababaB"),
+            ],
+        )
+
 
 def test_running_and_state():
     check_running_and_state(KnuthBendix)