dirbrowser: move parent dir logic to own function

qutebrowser/browser/network/filescheme.py

@@ -68,6 +68,18 @@ def is_root(directory):
     return os.path.dirname(directory) == directory
 
 
+def parent_dir(directory):
+    """Return the parent directory for the given directory.
+
+    Args:
+        directory: The path to the directory.
+
+    Return:
+        The path to the parent directory.
+    """
+    return os.path.normpath(os.path.join(directory, os.pardir))
+
+
 def dirbrowser_html(path):
     """Get the directory browser web page.
 
@@ -82,7 +94,7 @@ def dirbrowser_html(path):
     if is_root(path):
         parent = None
     else:
-        parent = os.path.normpath(os.path.join(path, '..'))
+        parent = parent_dir(path)
 
     try:
         all_files = os.listdir(path)

tests/unit/browser/network/test_filescheme.py

@@ -77,6 +77,29 @@ class TestIsRoot:
         assert filescheme.is_root(directory) == is_root
 
 
+class TestParentDir:
+
+    @pytest.mark.windows
+    @pytest.mark.parametrize('directory, parent', [
+        ('C:\\foo\\bar', 'C:\\foo'),
+        ('C:\\foo', 'C:\\'),
+        ('C:\\foo\\', 'C:\\'),
+        ('C:\\', 'C:\\'),
+    ])
+    def test_windows(self, directory, parent):
+        assert filescheme.parent_dir(directory) == parent
+
+    @pytest.mark.posix
+    @pytest.mark.parametrize('directory, parent', [
+        ('/home/foo', '/home'),
+        ('/home', '/'),
+        ('/home/', '/'),
+        ('/', '/'),
+    ])
+    def test_posix(self, directory, parent):
+        assert filescheme.parent_dir(directory) == parent
+
+
 def _file_url(path):
     """Return a file:// url (as string) for the given LocalPath.