diff --git a/kafka/producer/kafka.py b/kafka/producer/kafka.py
index 876ad3154..6d1dd079e 100644
--- a/kafka/producer/kafka.py
+++ b/kafka/producer/kafka.py
@@ -646,7 +646,7 @@ def _cleanup_factory(self):
         _self = weakref.proxy(self)
         def wrapper():
             try:
-                _self.close(timeout=0, null_logger=True)
+                _self.close(timeout=1, null_logger=True)
             except (ReferenceError, AttributeError):
                 pass
         return wrapper
diff --git a/kafka/producer/sender.py b/kafka/producer/sender.py
index 4e32b9854..e362a26d7 100644
--- a/kafka/producer/sender.py
+++ b/kafka/producer/sender.py
@@ -310,7 +310,7 @@ def _maybe_send_pending_request(self):
             return False
 
         log.debug("%s: Sending transactional request %s", str(self), next_request_handler.request)
-        while not self._force_close:
+        while self._running and not self._force_close:
             target_node = None
             try:
                 if next_request_handler.needs_coordinator():
@@ -325,7 +325,8 @@ def _maybe_send_pending_request(self):
                 else:
                     target_node = self._client.least_loaded_node()
                     if target_node is None:
-                        self._client.poll(future=self._metadata.request_update())
+                        self._client.poll(timeout_ms=self.config['retry_backoff_ms'],
+                                          future=self._metadata.request_update())
                     elif not self._client.await_ready(target_node, timeout_ms=self.config['request_timeout_ms']):
                         continue
 
diff --git a/test/producer/test_kip679_config.py b/test/producer/test_kip679_config.py
index 9169e7603..cfc11e7db 100644
--- a/test/producer/test_kip679_config.py
+++ b/test/producer/test_kip679_config.py
@@ -12,66 +12,52 @@
 # same process. Observable behavior on the producer instance (enable_idempotence
 # flag, _transaction_manager presence, config['acks']) is what callers actually
 # depend on, and is what these tests verify.
+#
+# These producers point at the default localhost:9092 with no broker running, so
+# the `with KafkaProducer(...) as p` form relies on close() tearing down the
+# Sender thread even though it never connects (see Sender._maybe_send_pending_request).
 
 
 class TestDefaultsAreIdempotent:
     """KIP-679: defaults instantiate an idempotent producer with acks=all."""
 
     def test_bare_construct_is_idempotent(self):
-        p = KafkaProducer(api_version=(0, 11))
-        try:
+        with KafkaProducer(api_version=(0, 11)) as p:
             assert p.config['enable_idempotence'] is True
             assert p.config['acks'] == -1
             assert p._transaction_manager is not None
             assert p._transaction_manager.is_transactional() is False
-        finally:
-            p.close(timeout=0)
 
     def test_opt_out_disables_idempotence_but_keeps_acks_default(self):
-        p = KafkaProducer(enable_idempotence=False, api_version=(0, 11))
-        try:
+        with KafkaProducer(enable_idempotence=False, api_version=(0, 11)) as p:
             assert p.config['enable_idempotence'] is False
             assert p.config['acks'] == -1
             assert p._transaction_manager is None
-        finally:
-            p.close(timeout=0)
 
 
 class TestDefaultIdempotenceSilentDisable:
     """User-provided incompatible config + default idempotence -> silent disable."""
 
     def test_acks_1_silently_disables(self):
-        p = KafkaProducer(acks=1, api_version=(0, 11))
-        try:
+        with KafkaProducer(acks=1, api_version=(0, 11)) as p:
             assert p.config['enable_idempotence'] is False
             assert p.config['acks'] == 1
             assert p._transaction_manager is None
-        finally:
-            p.close(timeout=0)
 
     def test_acks_0_silently_disables(self):
-        p = KafkaProducer(acks=0, api_version=(0, 11))
-        try:
+        with KafkaProducer(acks=0, api_version=(0, 11)) as p:
             assert p.config['enable_idempotence'] is False
             assert p._transaction_manager is None
-        finally:
-            p.close(timeout=0)
 
     def test_retries_zero_silently_disables(self):
-        p = KafkaProducer(retries=0, api_version=(0, 11))
-        try:
+        with KafkaProducer(retries=0, api_version=(0, 11)) as p:
             assert p.config['enable_idempotence'] is False
             assert p._transaction_manager is None
-        finally:
-            p.close(timeout=0)
 
     def test_max_in_flight_too_high_silently_disables(self):
-        p = KafkaProducer(max_in_flight_requests_per_connection=10, api_version=(0, 11))
-        try:
+        with KafkaProducer(max_in_flight_requests_per_connection=10, api_version=(0, 11)) as p:
             assert p.config['enable_idempotence'] is False
             assert p._transaction_manager is None
-        finally:
-            p.close(timeout=0)
 
 
 class TestOldBrokerFallback:
@@ -79,14 +65,11 @@ class TestOldBrokerFallback:
     acks=-1 retained (acks=all is valid on any wire version)."""
 
     def test_old_broker_silently_disables(self):
-        p = KafkaProducer(api_version=(0, 10))
-        try:
+        with KafkaProducer(api_version=(0, 10)) as p:
             assert p.config['enable_idempotence'] is False
             # Per KIP-679 + project decision: acks stays at -1 even on old brokers.
             assert p.config['acks'] == -1
             assert p._transaction_manager is None
-        finally:
-            p.close(timeout=0)
 
 
 class TestExplicitIdempotenceConflicts:
@@ -139,16 +122,13 @@ def test_multiple_conflicts_named_together(self):
 
     def test_acks_all_string_accepted(self):
         """'all' normalizes to -1 before the conflict check fires."""
-        p = KafkaProducer(
+        with KafkaProducer(
             enable_idempotence=True,
             acks='all',
             api_version=(0, 11),
-        )
-        try:
+        ) as p:
             assert p.config['acks'] == -1
             assert p._transaction_manager is not None
-        finally:
-            p.close(timeout=0)
 
     def test_old_broker_with_explicit_idempotence_raises(self):
         with pytest.raises(Errors.KafkaConfigurationError, match="api_version"):