account for None output in RandomWalk and RandomWord oracles

Author: Edi Muskardin

aalpy/oracles/RandomWalkEqOracle.py

@@ -68,7 +68,7 @@ def find_cex(self, hypothesis):
 
                 self.sul.post()
                 return inputs
-            elif out_hyp is None:
+            elif out_hyp is None and self.automata_type != 'det':
                 if self.reset_after_cex:
                     self.random_steps_done = 0
                 self.sul.post()

aalpy/oracles/RandomWordEqOracle.py

@@ -72,7 +72,7 @@ def find_cex(self, hypothesis):
                     self.sul.post()
                     return inputs
 
-                elif out_hyp is None:
+                elif out_hyp is None and self.automata_type != 'det':
                     self.sul.post()
 
                     if self.reset_after_cex: