diff --git a/editor.py b/editor.py
index 19b96c37..fcf16386 100644
--- a/editor.py
+++ b/editor.py
@@ -68,11 +68,14 @@ least one of these before using this command.""", file=sys.stderr)
   def EditString(cls, data):
     """Opens an editor to edit the given content.
 
-       Args:
-         data        : the text to edit
+    Args:
+      data: The text to edit.
 
-      Returns:
-        new value of edited text; None if editing did not succeed
+    Returns:
+      New value of edited text.
+
+    Raises:
+      EditorError: The editor failed to run.
     """
     editor = cls._GetEditor()
     if editor == ':':
@@ -80,7 +83,7 @@ least one of these before using this command.""", file=sys.stderr)
 
     fd, path = tempfile.mkstemp()
     try:
-      os.write(fd, data)
+      os.write(fd, data.encode('utf-8'))
       os.close(fd)
       fd = None
 
@@ -106,8 +109,8 @@ least one of these before using this command.""", file=sys.stderr)
         raise EditorError('editor failed with exit status %d: %s %s'
           % (rc, editor, path))
 
-      with open(path) as fd2:
-        return fd2.read()
+      with open(path, mode='rb') as fd2:
+        return fd2.read().decode('utf-8')
     finally:
       if fd:
         os.close(fd)
diff --git a/subcmds/upload.py b/subcmds/upload.py
index d0dd3837..5c12aaee 100644
--- a/subcmds/upload.py
+++ b/subcmds/upload.py
@@ -271,11 +271,6 @@ Gerrit Code Review:  https://www.gerritcodereview.com/
       branches[project.name] = b
     script.append('')
 
-    script = [ x.encode('utf-8')
-             if issubclass(type(x), unicode)
-             else x
-             for x in script ]
-
     script = Editor.EditString("\n".join(script)).split("\n")
 
     project_re = re.compile(r'^#?\s*project\s*([^\s]+)/:$')
diff --git a/tests/test_editor.py b/tests/test_editor.py
new file mode 100644
index 00000000..fbcfcdbd
--- /dev/null
+++ b/tests/test_editor.py
@@ -0,0 +1,60 @@
+# -*- coding:utf-8 -*-
+#
+# Copyright (C) 2019 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Unittests for the editor.py module."""
+
+from __future__ import print_function
+
+import unittest
+
+from editor import Editor
+
+
+class EditorTestCase(unittest.TestCase):
+  """Take care of resetting Editor state across tests."""
+
+  def setUp(self):
+    self.setEditor(None)
+
+  def tearDown(self):
+    self.setEditor(None)
+
+  @staticmethod
+  def setEditor(editor):
+    Editor._editor = editor
+
+
+class GetEditor(EditorTestCase):
+  """Check GetEditor behavior."""
+
+  def test_basic(self):
+    """Basic checking of _GetEditor."""
+    self.setEditor(':')
+    self.assertEqual(':', Editor._GetEditor())
+
+
+class EditString(EditorTestCase):
+  """Check EditString behavior."""
+
+  def test_no_editor(self):
+    """Check behavior when no editor is available."""
+    self.setEditor(':')
+    self.assertEqual('foo', Editor.EditString('foo'))
+
+  def test_cat_editor(self):
+    """Check behavior when editor is `cat`."""
+    self.setEditor('cat')
+    self.assertEqual('foo', Editor.EditString('foo'))