Merge pull request #659 from ranjinidas/master

Added Slow TF2T

axelrod/strategies/_strategies.py

@@ -56,7 +56,7 @@
 from .titfortat import (
     TitForTat, TitFor2Tats, TwoTitsForTat, Bully, SneakyTitForTat,
     SuspiciousTitForTat, AntiTitForTat, HardTitForTat, HardTitFor2Tats,
-    OmegaTFT, Gradual, ContriteTitForTat)
+    OmegaTFT, Gradual, ContriteTitForTat, SlowTitForTwoTats)
 
 
 # Note: Meta* strategies are handled in .__init__.py
@@ -166,6 +166,7 @@
     Ripoff,
     RiskyQLearner,
     Shubik,
+    SlowTitForTwoTats,
     SneakyTitForTat,
     SoftGrudger,
     SoftJoss,

axelrod/strategies/titfortat.py

@@ -386,3 +386,36 @@ def reset(self):
         Player.reset(self)
         self.contrite = False
         self._recorded_history = []
+
+
+class SlowTitForTwoTats(Player):
+    """
+    A player plays C twice, then if the opponent plays the same move twice, 
+    plays that move 
+    """
+
+    name = 'Slow Tit For Two Tats'
+    classifier = {
+        'memory_depth': 2, 
+        'stochastic': False,
+        'makes_use_of': set(),
+        'inspects_source': False,
+        'manipulates_source': False,
+        'manipulates_state': False
+    }
+
+    def strategy(self, opponent):
+
+        #Start with two cooperations
+        if len(self.history) < 2:
+            return C
+
+        #Mimic if opponent plays the same move twice
+        if opponent.history[-2] == opponent.history[-1]:
+            return opponent.history[-1]
+
+        #Otherwise cooperate
+        return C
+
+
+

axelrod/tests/unit/test_punisher.py

@@ -116,3 +116,4 @@ def test_reset_method(self):
         self.assertEqual(P1.history, [])
         self.assertEqual(P1.grudged, False)
         self.assertEqual(P1.grudge_memory, 0)
+

axelrod/tests/unit/test_titfortat.py

@@ -432,8 +432,35 @@ def test_strategy_with_noise(self):
         self.assertEqual(opponent.history, [C, D, D, D])
         self.assertFalse(ctft.contrite)
 
+
     def test_reset_cleans_all(self):
         p = self.player()
         p.contrite = True
         p.reset()
         self.assertFalse(p.contrite)
+
+class TestSlowTitForTwoTats(TestPlayer):
+
+    name = "Slow Tit For Two Tats"
+    player = axelrod.SlowTitForTwoTats
+    expected_classifier = {
+        'memory_depth': 2,
+        'stochastic': False,
+        'makes_use_of': set(),
+        'inspects_source': False,
+        'manipulates_source': False,
+        'manipulates_state': False
+    }
+
+    def test_strategy(self):
+        """Starts by cooperating."""
+        self.first_play_test(C)
+
+    def test_effect_of_strategy(self):
+        """If opponent plays the same move twice, repeats last action of opponent history."""
+        self.responses_test([C]*2, [C, C], [C])
+        self.responses_test([C]*3, [C, D, C], [C])
+        self.responses_test([C]*3, [C, D, D], [D])
+
+
+