Part #2 of shlex.split fix

The pane-border-format option was introduced in tmux 2.3, so do not run a test
for that on older versions.

Author: kaushalmodi

libtmux/window.py

@@ -229,7 +229,7 @@ def show_window_option(self, option, g=False):
         if not len(cmd.stdout):
             return None
 
-        option = [item.split(' ') for item in cmd.stdout][0]
+        option = [shlex.split(item) for item in cmd.stdout][0]
 
         if option[1].isdigit():
             option = (option[0], int(option[1]))

tests/test_window.py

@@ -174,13 +174,14 @@ def test_set_show_window_options(session):
     window.set_window_option('main-pane-height', 20)
     assert window.show_window_options('main-pane-height') == 20
 
-    window.set_window_option('pane-border-format', ' #P ')
-    assert window.show_window_options('pane-border-format') == [' #P ']
-
     window.set_window_option('main-pane-height', 40)
     assert window.show_window_options('main-pane-height') == 40
     assert window.show_window_options()['main-pane-height'] == 40
 
+    if has_gte_version('2.3'):
+        window.set_window_option('pane-border-format', ' #P ')
+        assert window.show_window_options('pane-border-format') == ' #P '
+
 
 def test_empty_window_option_returns_None(session):
     window = session.new_window(window_name='test_window')