Implemented Retry class inspired by KazooRetry

tests/test_utils.py

@@ -2,7 +2,8 @@ import os
 import time
 import unittest
 
-from helpers.utils import reap_children, sigchld_handler, sigterm_handler, sleep
+from helpers import DCSError
+from helpers.utils import Retry, RetryFailedError, reap_children, sigchld_handler, sigterm_handler, sleep
 
 
 def nop(*args, **kwargs):
@@ -43,3 +44,58 @@ class TestUtils(unittest.TestCase):
     def test_sleep(self):
         time.sleep = time_sleep
         sleep(0.01)
+
+
+class TestRetrySleeper(unittest.TestCase):
+
+    def _pass(self):
+        pass
+
+    def _fail(self, times=1):
+        scope = dict(times=0)
+
+        def inner():
+            if scope['times'] >= times:
+                pass
+            else:
+                scope['times'] += 1
+                raise DCSError('Failed!')
+        return inner
+
+    def _makeOne(self, *args, **kwargs):
+        return Retry(*args, **kwargs)
+
+    def test_reset(self):
+        retry = self._makeOne(delay=0, max_tries=2)
+        retry(self._fail())
+        self.assertEquals(retry._attempts, 1)
+        retry.reset()
+        self.assertEquals(retry._attempts, 0)
+
+    def test_too_many_tries(self):
+        retry = self._makeOne(delay=0)
+        self.assertRaises(RetryFailedError, retry, self._fail(times=999))
+        self.assertEquals(retry._attempts, 1)
+
+    def test_maximum_delay(self):
+        def sleep_func(_time):
+            pass
+
+        retry = self._makeOne(delay=10, max_tries=100, sleep_func=sleep_func)
+        retry(self._fail(times=10))
+        self.assertTrue(retry._cur_delay < 4000, retry._cur_delay)
+        # gevent's sleep function is picky about the type
+        self.assertEquals(type(retry._cur_delay), float)
+
+    def test_deadline(self):
+        def sleep_func(_time):
+            pass
+
+        retry = self._makeOne(deadline=0.0001, sleep_func=sleep_func)
+        self.assertRaises(RetryFailedError, retry, self._fail(times=10))
+
+    def test_copy(self):
+        _sleep = lambda t: None
+        retry = self._makeOne(sleep_func=_sleep)
+        rcopy = retry.copy()
+        self.assertTrue(rcopy.sleep_func is _sleep)