PYTHON-2124 Assert no gc.garbage at test suite teardown and enable debug output

setup.py

@@ -122,9 +122,9 @@ class test(Command):
             suite = unittest.defaultTestLoader.loadTestsFromName(
                 self.test_suite)
         if self.xunit_output:
-            from xmlrunner import XMLTestRunner
-            runner = XMLTestRunner(verbosity=2, failfast=self.failfast,
-                                   output=self.xunit_output)
+            from test import PymongoXMLTestRunner
+            runner = PymongoXMLTestRunner(verbosity=2, failfast=self.failfast,
+                                          output=self.xunit_output)
         else:
             runner = PymongoTestRunner(verbosity=2, failfast=self.failfast)
         result = runner.run(suite)

test/__init__.py

@@ -15,6 +15,7 @@
 """Test suite for pymongo, bson, and gridfs.
 """
 
+import gc
 import os
 import socket
 import sys
@@ -23,6 +24,12 @@ import time
 import unittest
 import warnings
 
+try:
+    from xmlrunner import XMLTestRunner
+    HAVE_XML = True
+except ImportError:
+    HAVE_XML = False
+
 try:
     import ipaddress
     HAVE_IPADDRESS = True
@@ -53,6 +60,13 @@ try:
 except ImportError:
     pass
 
+# Enable debug output for uncollectable objects. PyPy does not have set_debug.
+if hasattr(gc, 'set_debug'):
+    gc.set_debug(
+        gc.DEBUG_UNCOLLECTABLE |
+        getattr(gc, 'DEBUG_OBJECTS', 0) |
+        getattr(gc, 'DEBUG_INSTANCES', 0))
+
 # The host and port of a single mongod or mongos, or the seed host
 # for a replica set.
 host = os.environ.get("DB_IP", 'localhost')
@@ -779,22 +793,38 @@ def setup():
 
 
 def teardown():
+    garbage = []
+    for g in gc.garbage:
+        garbage.append('GARBAGE: %r' % (g,))
+        garbage.append('  gc.get_referents: %r' % (gc.get_referents(g),))
+        garbage.append('  gc.get_referrers: %r' % (gc.get_referrers(g),))
+    if garbage:
+        assert False, '\n'.join(garbage)
     c = client_context.client
-    c.drop_database("pymongo-pooling-tests")
-    c.drop_database("pymongo_test")
-    c.drop_database("pymongo_test1")
-    c.drop_database("pymongo_test2")
-    c.drop_database("pymongo_test_mike")
-    c.drop_database("pymongo_test_bernie")
+    if c:
+        c.drop_database("pymongo-pooling-tests")
+        c.drop_database("pymongo_test")
+        c.drop_database("pymongo_test1")
+        c.drop_database("pymongo_test2")
+        c.drop_database("pymongo_test_mike")
+        c.drop_database("pymongo_test_bernie")
+        c.close()
 
 
 class PymongoTestRunner(unittest.TextTestRunner):
     def run(self, test):
         setup()
         result = super(PymongoTestRunner, self).run(test)
-        try:
+        teardown()
+        return result
+
+
+if HAVE_XML:
+    class PymongoXMLTestRunner(XMLTestRunner):
+        def run(self, test):
+            setup()
+            result = super(PymongoXMLTestRunner, self).run(test)
             teardown()
-        finally:
             return result
 
 

test/test_change_stream.py

@@ -575,12 +575,13 @@ class ProseSpecTestsMixin(object):
                     change_stream._cursor.close()
                     raise OperationFailure('Mock server error', code=code)
 
-                original_try_next = change_stream._cursor._try_next
+                original_cursor = change_stream._cursor
                 change_stream._cursor._try_next = mock_try_next
                 try:
                     yield
                 finally:
-                    change_stream._cursor._try_next = original_try_next
+                    # Un patch the instance.
+                    del original_cursor._try_next
 
         for code in TEST_ERROR_CODES:
             with self.change_stream() as change_stream:

test/test_client.py

@@ -1514,6 +1514,8 @@ class TestClient(IntegrationTest):
             return original_connect(*args, **kwargs)
 
         pool.connect = stall_connect
+        # Un-patch Pool.connect to break the cyclic reference.
+        self.addCleanup(delattr, pool, 'connect')
 
         # Wait for the background thread to start creating connections
         wait_until(lambda: len(pool.sockets) > 1, 'start creating connections')

test/test_cmap.py

@@ -376,6 +376,8 @@ class TestCMAP(IntegrationTest):
             sock_info.check_auth = functools.partial(mock_check_auth, sock_info)
             return sock_info
         pool.connect = mock_connect
+        # Un-patch Pool.connect to break the cyclic reference.
+        self.addCleanup(delattr, pool, 'connect')
 
         # Attempt to create a new connection.
         with self.assertRaisesRegex(ConnectionFailure, 'auth failed'):