Add tests for exponential recon. policy

cassandra/policies.py

@@ -158,7 +158,7 @@ class ExponentialReconnectionPolicy(object):
         self.max_delay = max_delay
 
     def new_schedule(self):
-        return (min(self.base_delay * (i ** 2), self.max_delay) for i in xrange(64))
+        return (min(self.base_delay * (2 ** i), self.max_delay) for i in xrange(64))
 
 
 class WriteType(object):

tests/test_policies.py

@@ -2,7 +2,8 @@ import unittest
 from threading import Thread
 
 from cassandra.policies import (RoundRobinPolicy, DCAwareRoundRobinPolicy,
-                                SimpleConvictionPolicy, HostDistance)
+                                SimpleConvictionPolicy, HostDistance,
+                                ExponentialReconnectionPolicy)
 from cassandra.pool import Host
 
 class TestRoundRobinPolicy(unittest.TestCase):
@@ -107,8 +108,8 @@ class TestDCAwareRoundRobinPolicy(unittest.TestCase):
         second_remote_host = Host("ip3", SimpleConvictionPolicy)
         second_remote_host.set_location_info("dc2", "rack1")
         policy.populate(None, [host, remote_host, second_remote_host])
-        self.assertEqual(policy.distance(remote_host), HostDistance.REMOTE)
+        distances = set([policy.distance(remote_host), policy.distance(second_remote_host)])
-        self.assertEqual(policy.distance(second_remote_host), HostDistance.IGNORED)
+        self.assertEqual(distances, set([HostDistance.REMOTE, HostDistance.IGNORED]))
 
     def test_status_updates(self):
         hosts = [Host(i, SimpleConvictionPolicy) for i in range(4)]
@@ -137,3 +138,23 @@ class TestDCAwareRoundRobinPolicy(unittest.TestCase):
 
         # since we have hosts in dc9000, the distance shouldn't be IGNORED
         self.assertEqual(policy.distance(new_remote_host), HostDistance.REMOTE)
+
+
+class ExponentialReconnectionPolicyTest(unittest.TestCase):
+
+    def test_bad_vals(self):
+        self.assertRaises(ValueError, ExponentialReconnectionPolicy, -1, 0)
+        self.assertRaises(ValueError, ExponentialReconnectionPolicy, 0, -1)
+        self.assertRaises(ValueError, ExponentialReconnectionPolicy, 9000, 1)
+
+    def test_schedule(self):
+        policy = ExponentialReconnectionPolicy(base_delay=2, max_delay=100)
+        schedule = list(policy.new_schedule())
+        self.assertEqual(len(schedule), 64)
+        for i, delay in enumerate(schedule):
+            if i == 0:
+                self.assertEqual(delay, 2)
+            elif i < 6:
+                self.assertEqual(delay, schedule[i - 1] * 2)
+            else:
+                self.assertEqual(delay, 100)