Change polling the existing lock from every 0.5s to every half of ttl

Author: jfan666

pytest_lab/locker.py

@@ -135,7 +135,7 @@ def check_lock(record):
                     record = self.backend.read(key)
                     if not record:
                         return True
-                    time.sleep(0.5)
+                    time.sleep(record.ttl // 2)
             else:
                 return True
 
@@ -144,7 +144,7 @@ def check_lock(record):
             if not wait_on_locks:
                 raise ResourceLocked(
                     '{} is currently locked by {}'.format(key, record.value))
-            while True:
+            while wait_on_locks:
                 if check_lock(record):
                     break