fix Schrödinger memory resource (#229)

fs/_version.py

@@ -1,3 +1,3 @@
 """Version, used in module and setup.py.
 """
-__version__ = "2.1.1"
+__version__ = "2.1.2a0"

fs/memoryfs.py

@@ -414,6 +414,9 @@ def openbin(self, path, mode="r", buffering=-1, **options):
         _path = self.validatepath(path)
         dir_path, file_name = split(_path)
 
+        if not file_name:
+            raise errors.FileExpected(path)
+
         with self._lock:
             parent_dir_entry = self._get_dir_entry(dir_path)
             if parent_dir_entry is None or not parent_dir_entry.is_dir:

fs/test.py

@@ -329,6 +329,12 @@ def assert_text(self, path, contents):
         self.assertEqual(data, contents)
         self.assertIsInstance(data, text_type)
 
+    def test_root_dir(self):
+        with self.assertRaises(errors.FileExpected):
+            self.fs.open("/")
+        with self.assertRaises(errors.FileExpected):
+            self.fs.openbin("/")
+
     def test_appendbytes(self):
         with self.assertRaises(TypeError):
             self.fs.appendbytes("foo", "bar")