Make sure editor test doesn't run on Windows

tests/end2end/features/test_editor_bdd.py

@@ -26,6 +26,8 @@ import signal
 import pytest_bdd as bdd
 bdd.scenarios('editor.feature')
 
+from qutebrowser.utils import utils
+
 
 @bdd.when(bdd.parsers.parse('I set up a fake editor replacing "{text}" by '
                             '"{replacement}"'))
@@ -71,6 +73,7 @@ def set_up_editor_empty(quteproc, tmpdir):
 @bdd.when(bdd.parsers.parse('I set up a fake editor that waits'))
 def set_up_editor_wait(quteproc, tmpdir):
     """Set up editor.command to a small python script inserting a text."""
+    assert not utils.is_windows
     pidfile = tmpdir / 'editor_pid'
     script = tmpdir / 'script.py'
     script.write(textwrap.dedent("""