Cleanup / assertions

strategy.py

@@ -235,7 +235,7 @@ class State:
     def gen_moves(self):
         yield self
 
-        for src in self.gen_shift(not self.colbusy(self.exa)):
+        for src in self.gen_shift(True):
             yield from src.gen_stationary()
 
             for get in src.gen_get():
@@ -315,9 +315,7 @@ class State:
             return self.force(DROP)
 
         pool = deque(self.gen_moves())
-
-        if len(pool) == 0:
-            return self.force()
+        assert len(pool) > 0
 
         best_score = ()
 
@@ -333,6 +331,7 @@ class State:
 
             for i in range(len(pool)):
                 state = pool.popleft()
+                assert state.held == NOBLOCK
                 if state.score == best:
                     pool.append(state)