PYTHON-1872 Follow-on SrvMonitor testing work

Author: prashantmital

test/test_srv_polling.py

@@ -33,7 +33,7 @@
 WAIT_TIME = 0.1
 
 
-class SRVPollingKnobs(object):
+class SrvPollingKnobs(object):
  def __init__(self, ttl_time=None, min_srv_rescan_interval=None,
  dns_resolver_nodelist_response=None,
  count_resolver_calls=False):
@@ -80,7 +80,7 @@ def __exit__(self, exc_type, exc_val, exc_tb):
  self.disable()
 
 
-class TestSRVPolling(unittest.TestCase):
+class TestSrvPolling(unittest.TestCase):
 
  BASE_SRV_RESPONSE = [
  ("localhost.test.build.10gen.cc", 27017),
@@ -113,7 +113,7 @@ def predicate():
  if set(expected_nodelist) == set(nodelist):
  return True
  return False
- wait_until(predicate, "see expected nodelist", timeout=10*WAIT_TIME)
+ wait_until(predicate, "see expected nodelist", timeout=100*WAIT_TIME)
 
  def assert_nodelist_nochange(self, expected_nodelist, client):
  """Check if the client._topology ever deviates from seeing all nodes
@@ -148,15 +148,15 @@ def dns_resolver_response():
  expected_response = self.BASE_SRV_RESPONSE
 
  # Patch timeouts to ensure short test running times.
- with SRVPollingKnobs(
+ with SrvPollingKnobs(
  ttl_time=WAIT_TIME, min_srv_rescan_interval=WAIT_TIME):
- mc = MongoClient(self.CONNECTION_STRING)
- self.assert_nodelist_change(self.BASE_SRV_RESPONSE, mc)
+ client = MongoClient(self.CONNECTION_STRING)
+ self.assert_nodelist_change(self.BASE_SRV_RESPONSE, client)
  # Patch list of hosts returned by DNS query.
- with SRVPollingKnobs(
+ with SrvPollingKnobs(
  dns_resolver_nodelist_response=dns_resolver_response,
  count_resolver_calls=count_resolver_calls):
- assertion_method(expected_response, mc)
+ assertion_method(expected_response, client)
 
  def test_addition(self):
  response = self.BASE_SRV_RESPONSE[:]
@@ -198,13 +198,27 @@ def test_dns_record_lookup_empty(self):
  response = []
  self.run_scenario(response, False)
 
- def _test_recover_from_initial(self, response_callback):
- with SRVPollingKnobs(
+ def _test_recover_from_initial(self, initial_callback):
+ # Construct a valid final response callback distinct from base.
+ response_final = self.BASE_SRV_RESPONSE[:]
+ response_final.pop()
+ def final_callback():
+ return response_final
+
+ with SrvPollingKnobs(
  ttl_time=WAIT_TIME, min_srv_rescan_interval=WAIT_TIME,
- dns_resolver_nodelist_response=response_callback,
+ dns_resolver_nodelist_response=initial_callback,
  count_resolver_calls=True):
- mc = MongoClient(self.CONNECTION_STRING)
- self.assert_nodelist_nochange(self.BASE_SRV_RESPONSE, mc)
+ # Client uses unpatched method to get initial nodelist
+ client = MongoClient(self.CONNECTION_STRING)
+ # Invalid DNS resolver response should not change nodelist.
+ self.assert_nodelist_nochange(self.BASE_SRV_RESPONSE, client)
+
+ with SrvPollingKnobs(
+ ttl_time=WAIT_TIME, min_srv_rescan_interval=WAIT_TIME,
+ dns_resolver_nodelist_response=final_callback):
+ # Nodelist should reflect new valid DNS resolver response.
+ self.assert_nodelist_change(response_final, client)
 
  def test_recover_from_initially_empty_seedlist(self):
  def empty_seedlist():