diff --git a/libtmux/session.py b/libtmux/session.py
index ca7652461..e5299fc83 100644
--- a/libtmux/session.py
+++ b/libtmux/session.py
@@ -18,9 +18,12 @@
     has_version,
     session_check_name,
 )
-from .pane import Pane
 from .window import Window
 
+if t.TYPE_CHECKING:
+    from .pane import Pane
+
+
 logger = logging.getLogger(__name__)
 
 
@@ -367,7 +370,7 @@ def select_window(self, target_window: str) -> Window:
         return self.attached_window
 
     @property
-    def attached_pane(self) -> t.Optional[Pane]:
+    def attached_pane(self) -> t.Optional["Pane"]:
         """Return active :class:`Pane` object."""
 
         return self.attached_window.attached_pane
diff --git a/tests/__init__.py b/tests/__init__.py
new file mode 100644
index 000000000..e69de29bb
diff --git a/tests/test_server.py b/tests/test_server.py
index 0e45f7d09..1c690287e 100644
--- a/tests/test_server.py
+++ b/tests/test_server.py
@@ -1,8 +1,8 @@
 """Test for libtmux Server object."""
 import logging
 
-from libtmux import Server
 from libtmux.common import has_gte_version
+from libtmux.server import Server
 
 logger = logging.getLogger(__name__)
 
diff --git a/tests/test_session.py b/tests/test_session.py
index 4b4a835f9..cca21a88a 100644
--- a/tests/test_session.py
+++ b/tests/test_session.py
@@ -3,9 +3,12 @@
 
 import pytest
 
-from libtmux import Pane, Session, Window, exc
+from libtmux import exc
 from libtmux.common import has_gte_version
+from libtmux.pane import Pane
+from libtmux.session import Session
 from libtmux.test import TEST_SESSION_PREFIX, namer
+from libtmux.window import Window
 
 logger = logging.getLogger(__name__)
 
diff --git a/tests/test_tmuxobject.py b/tests/test_tmuxobject.py
index 02c3446f8..40813e76d 100644
--- a/tests/test_tmuxobject.py
+++ b/tests/test_tmuxobject.py
@@ -1,8 +1,10 @@
 """Tests for libtmux TmuxRelationalObject and TmuxMappingObject."""
 import logging
 
-from libtmux import Pane, Session, Window
+from libtmux.pane import Pane
+from libtmux.session import Session
 from libtmux.test import TEST_SESSION_PREFIX, namer
+from libtmux.window import Window
 
 logger = logging.getLogger(__name__)
 
diff --git a/tests/test_window.py b/tests/test_window.py
index 0c4029ac5..bc0492a60 100644
--- a/tests/test_window.py
+++ b/tests/test_window.py
@@ -3,8 +3,11 @@
 
 import pytest
 
-from libtmux import Pane, Server, Window, exc
+from libtmux import exc
 from libtmux.common import has_gte_version
+from libtmux.pane import Pane
+from libtmux.server import Server
+from libtmux.window import Window
 
 logger = logging.getLogger(__name__)