Use catch_warnings to test warnings.

Author: behackett

test/__init__.py

@@ -44,10 +44,8 @@
 
 
 def setup():
-    # Make sure warnings are always raised, regardless of
-    # python version.
     warnings.resetwarnings()
-    warnings.simplefilter("always")
+    warnings.simplefilter("ignore")
 
 
 def teardown():

test/test_collection.py

@@ -217,16 +217,10 @@ def test_ensure_index(self):
     def test_deprecated_ttl_index_kwarg(self):
         db = self.db
 
-        # In Python 2.6+ we could use the catch_warnings context
-        # manager to test this warning nicely. As we can't do that
-        # we must test raising errors before the ignore filter is applied.
-        warnings.simplefilter("error", DeprecationWarning)
-        try:
+        with warnings.catch_warnings():
+            warnings.simplefilter("error", DeprecationWarning)
             self.assertRaises(DeprecationWarning, lambda:
                               db.test.ensure_index("goodbye", ttl=10))
-        finally:
-            warnings.resetwarnings()
-            warnings.simplefilter("ignore")
 
         self.assertEqual("goodbye_1",
                          db.test.ensure_index("goodbye", ttl=10))

test/test_common.py

@@ -16,7 +16,6 @@
 
 import sys
 import uuid
-import warnings
 
 sys.path[0:0] = [""]
 

test/test_database.py

@@ -351,15 +351,12 @@ def test_authenticate_add_remove_user(self):
                           "user", 'password', True, roles=['read'])
 
         if version.at_least(self.client, (2, 5, 3, -1)):
-            warnings.simplefilter("error", DeprecationWarning)
-            try:
+            with warnings.catch_warnings():
+                warnings.simplefilter("error", DeprecationWarning)
                 self.assertRaises(DeprecationWarning, db.add_user,
                                   "user", "password")
                 self.assertRaises(DeprecationWarning, db.add_user,
                                   "user", "password", True)
-            finally:
-                warnings.resetwarnings()
-                warnings.simplefilter("ignore")
 
             self.assertRaises(ConfigurationError, db.add_user,
                               "user", "password", digestPassword=True)
@@ -930,18 +927,15 @@ def test_command_response_without_ok(self):
             self.fail("_check_command_response didn't raise OperationFailure")
 
     def test_command_read_pref_warning(self):
-        warnings.simplefilter("error", UserWarning)
-        try:
+        with warnings.catch_warnings():
+            warnings.simplefilter("error", UserWarning)
             self.assertRaises(UserWarning, self.client.pymongo_test.command,
                               'ping', read_preference=ReadPreference.SECONDARY)
             try:
                 self.client.pymongo_test.command(
                     'dbStats', read_preference=ReadPreference.SECONDARY)
             except UserWarning:
                 self.fail("Shouldn't have raised UserWarning.")
-        finally:
-            warnings.resetwarnings()
-            warnings.simplefilter("ignore")
 
     def test_command_max_time_ms(self):
         if not version.at_least(self.client, (2, 5, 3, -1)):