bpo-37520: Correct behavior for zipfile.Path.parent (GH-14638)

* bpo-37520: Correct behavior for zipfile.Path.parent

* 📜🤖 Added by blurb_it.
diff --git a/Lib/test/test_zipfile.py b/Lib/test/test_zipfile.py
index 19b550f..0c8ffcd 100644
--- a/Lib/test/test_zipfile.py
+++ b/Lib/test/test_zipfile.py
@@ -2514,5 +2514,16 @@
             assert (root / 'a').parent.at == ''
             assert (root / 'a' / 'b').parent.at == 'a/'
 
+    def test_dir_parent(self):
+        for zipfile_abcde in self.zipfile_abcde():
+            root = zipfile.Path(zipfile_abcde)
+            assert (root / 'b').parent.at == ''
+            assert (root / 'b/').parent.at == ''
+
+    def test_missing_dir_parent(self):
+        for zipfile_abcde in self.zipfile_abcde():
+            root = zipfile.Path(zipfile_abcde)
+            assert (root / 'missing dir/').parent.at == ''
+
 if __name__ == "__main__":
     unittest.main()