diff --git a/pymongo/pool.py b/pymongo/pool.py
index 5d62e4bee..15e5b4873 100644
--- a/pymongo/pool.py
+++ b/pymongo/pool.py
@@ -226,6 +226,9 @@ else:
 # main thread, to avoid the deadlock. See PYTHON-607.
 'foo'.encode('idna')
 
+# Remove after PYTHON-2712
+_MOCK_SERVICE_ID = False
+
 
 def _raise_connection_failure(address, error, msg_prefix=None):
     """Convert a socket.error to ConnectionFailure and raise it."""
@@ -600,7 +603,7 @@ class SocketInfo(object):
         doc = self.command('admin', cmd, publish_events=False,
                            exhaust_allowed=awaitable)
         # PYTHON-2712 will remove this topologyVersion fallback logic.
-        if self.opts.load_balanced:
+        if self.opts.load_balanced and _MOCK_SERVICE_ID:
             process_id = doc.get('topologyVersion', {}).get('processId')
             doc.setdefault('serviceId', process_id)
         ismaster = IsMaster(doc, awaitable=awaitable)
@@ -627,7 +630,7 @@ class SocketInfo(object):
         if self.opts.load_balanced:
             if not ismaster.service_id:
                 raise ConfigurationError(
-                    'Driver attempted to initialize in load balancing mode'
+                    'Driver attempted to initialize in load balancing mode,'
                     ' but the server does not support this mode')
             self.service_id = ismaster.service_id
             self.generation = self.pool_gen.get(self.service_id)
@@ -1338,11 +1341,11 @@ class Pool:
             raise
 
         sock_info = SocketInfo(sock, self, self.address, conn_id)
-        if self.handshake:
-            sock_info.ismaster(all_credentials)
-            self.is_writable = sock_info.is_writable
-
         try:
+            if self.handshake:
+                sock_info.ismaster(all_credentials)
+                self.is_writable = sock_info.is_writable
+
             sock_info.check_auth(all_credentials)
         except BaseException:
             sock_info.close_socket(ConnectionClosedReason.ERROR)
diff --git a/test/__init__.py b/test/__init__.py
index 9e76b28f5..1e76e58b8 100644
--- a/test/__init__.py
+++ b/test/__init__.py
@@ -97,6 +97,9 @@ TEST_LOADBALANCER = bool(os.environ.get("TEST_LOADBALANCER"))
 SINGLE_MONGOS_LB_URI = os.environ.get("SINGLE_MONGOS_LB_URI")
 MULTI_MONGOS_LB_URI = os.environ.get("MULTI_MONGOS_LB_URI")
 if TEST_LOADBALANCER:
+    # Remove after PYTHON-2712
+    from pymongo import pool
+    pool._MOCK_SERVICE_ID = True
     res = parse_uri(SINGLE_MONGOS_LB_URI)
     host, port = res['nodelist'][0]
     db_user = res['username'] or db_user
diff --git a/test/load_balancer/test_crud_unified.py b/test/load_balancer/test_crud_unified.py
index dfe0935bb..4363f293f 100644
--- a/test/load_balancer/test_crud_unified.py
+++ b/test/load_balancer/test_crud_unified.py
@@ -13,10 +13,10 @@
 # limitations under the License.
 
 import sys
-import unittest
 
 sys.path[0:0] = [""]
 
+from test import unittest
 from test.test_crud_unified import *
 
 if __name__ == '__main__':
diff --git a/test/load_balancer/test_dns.py b/test/load_balancer/test_dns.py
index 047b98b12..34e2329c8 100644
--- a/test/load_balancer/test_dns.py
+++ b/test/load_balancer/test_dns.py
@@ -13,10 +13,10 @@
 # limitations under the License.
 
 import sys
-import unittest
 
 sys.path[0:0] = [""]
 
+from test import unittest
 from test.test_dns import *
 
 if __name__ == '__main__':
diff --git a/test/load_balancer/test_load_balancer.py b/test/load_balancer/test_load_balancer.py
index 99f8855ca..77e824e59 100644
--- a/test/load_balancer/test_load_balancer.py
+++ b/test/load_balancer/test_load_balancer.py
@@ -14,38 +14,12 @@
 
 """Test the Load Balancer unified spec tests."""
 
-import os
 import sys
 
 sys.path[0:0] = [""]
 
-from test import unittest, IntegrationTest, client_context
-from test.utils import get_pool
-from test.unified_format import generate_test_classes
-
-# Location of JSON test specifications.
-TEST_PATH = os.path.join(
-    os.path.dirname(os.path.realpath(__file__)), 'unified')
-
-# Generate unified tests.
-globals().update(generate_test_classes(TEST_PATH, module=__name__))
-
-
-class TestLB(IntegrationTest):
-    @client_context.require_load_balancer
-    def test_unpin_committed_transaction(self):
-        pool = get_pool(self.client)
-        with self.client.start_session() as session:
-            with session.start_transaction():
-                self.assertEqual(pool.active_sockets, 0)
-                self.db.test.insert_one({}, session=session)
-                self.assertEqual(pool.active_sockets, 1)  # Pinned.
-            self.assertEqual(pool.active_sockets, 1)  # Still pinned.
-        self.assertEqual(pool.active_sockets, 0)  # Unpinned.
-
-    def test_client_can_be_reopened(self):
-        self.client.close()
-        self.db.test.find_one({})
+from test import unittest
+from test.test_load_balancer import *
 
 
 if __name__ == "__main__":
diff --git a/test/load_balancer/test_retryable_change_stream.py b/test/load_balancer/test_retryable_change_stream.py
index b7c902dd3..f08e27e9d 100644
--- a/test/load_balancer/test_retryable_change_stream.py
+++ b/test/load_balancer/test_retryable_change_stream.py
@@ -13,10 +13,10 @@
 # limitations under the License.
 
 import sys
-import unittest
 
 sys.path[0:0] = [""]
 
+from test import unittest
 from test.test_change_stream import *
 
 if __name__ == '__main__':
diff --git a/test/load_balancer/test_retryable_reads.py b/test/load_balancer/test_retryable_reads.py
index c5de3c907..73510fab7 100644
--- a/test/load_balancer/test_retryable_reads.py
+++ b/test/load_balancer/test_retryable_reads.py
@@ -13,10 +13,10 @@
 # limitations under the License.
 
 import sys
-import unittest
 
 sys.path[0:0] = [""]
 
+from test import unittest
 from test.test_retryable_reads import *
 
 if __name__ == '__main__':
diff --git a/test/load_balancer/test_retryable_writes.py b/test/load_balancer/test_retryable_writes.py
index 3800641b0..c920acb81 100644
--- a/test/load_balancer/test_retryable_writes.py
+++ b/test/load_balancer/test_retryable_writes.py
@@ -13,10 +13,10 @@
 # limitations under the License.
 
 import sys
-import unittest
 
 sys.path[0:0] = [""]
 
+from test import unittest
 from test.test_retryable_writes import *
 
 if __name__ == '__main__':
diff --git a/test/load_balancer/test_transactions_unified.py b/test/load_balancer/test_transactions_unified.py
index 257202804..d2f7eac94 100644
--- a/test/load_balancer/test_transactions_unified.py
+++ b/test/load_balancer/test_transactions_unified.py
@@ -13,10 +13,10 @@
 # limitations under the License.
 
 import sys
-import unittest
 
 sys.path[0:0] = [""]
 
+from test import unittest
 from test.test_transactions_unified import *
 
 if __name__ == '__main__':
diff --git a/test/load_balancer/test_uri_options.py b/test/load_balancer/test_uri_options.py
index b644d7d33..c7151d330 100644
--- a/test/load_balancer/test_uri_options.py
+++ b/test/load_balancer/test_uri_options.py
@@ -13,10 +13,10 @@
 # limitations under the License.
 
 import sys
-import unittest
 
 sys.path[0:0] = [""]
 
+from test import unittest
 from test.test_uri_spec import *
 
 if __name__ == '__main__':
diff --git a/test/load_balancer/test_versioned_api.py b/test/load_balancer/test_versioned_api.py
index 7e801968c..2b188a6b1 100644
--- a/test/load_balancer/test_versioned_api.py
+++ b/test/load_balancer/test_versioned_api.py
@@ -13,10 +13,10 @@
 # limitations under the License.
 
 import sys
-import unittest
 
 sys.path[0:0] = [""]
 
+from test import unittest
 from test.test_versioned_api import *
 
 if __name__ == '__main__':
diff --git a/test/test_load_balancer.py b/test/test_load_balancer.py
new file mode 100644
index 000000000..90bde87e5
--- /dev/null
+++ b/test/test_load_balancer.py
@@ -0,0 +1,52 @@
+# Copyright 2021-present MongoDB, Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Test the Load Balancer unified spec tests."""
+
+import os
+import sys
+
+sys.path[0:0] = [""]
+
+from test import unittest, IntegrationTest, client_context
+from test.utils import get_pool
+from test.unified_format import generate_test_classes
+
+# Location of JSON test specifications.
+TEST_PATH = os.path.join(
+    os.path.dirname(os.path.realpath(__file__)), 'load_balancer', 'unified')
+
+# Generate unified tests.
+globals().update(generate_test_classes(TEST_PATH, module=__name__))
+
+
+class TestLB(IntegrationTest):
+    @client_context.require_load_balancer
+    def test_unpin_committed_transaction(self):
+        pool = get_pool(self.client)
+        with self.client.start_session() as session:
+            with session.start_transaction():
+                self.assertEqual(pool.active_sockets, 0)
+                self.db.test.insert_one({}, session=session)
+                self.assertEqual(pool.active_sockets, 1)  # Pinned.
+            self.assertEqual(pool.active_sockets, 1)  # Still pinned.
+        self.assertEqual(pool.active_sockets, 0)  # Unpinned.
+
+    def test_client_can_be_reopened(self):
+        self.client.close()
+        self.db.test.find_one({})
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/test/unified_format.py b/test/unified_format.py
index d2433e5b4..284fee1ed 100644
--- a/test/unified_format.py
+++ b/test/unified_format.py
@@ -891,6 +891,10 @@ class UnifiedSpecTestMixinV1(IntegrationTest):
             if expect_error:
                 return self.process_error(exc, expect_error)
             raise
+        else:
+            if expect_error:
+                self.fail('Excepted error %s but "%s" succeeded: %s' % (
+                    expect_error, opname, result))
 
         if expect_result:
             actual = coerce_result(opname, result)