--- a/testing/marionette/harness/marionette_harness/tests/unit/unit-tests.ini
+++ b/testing/marionette/harness/marionette_harness/tests/unit/unit-tests.ini
@@ -106,17 +106,17 @@ skip-if = appname == 'fennec'
 [test_teardown_context_preserved.py]
 [test_file_upload.py]
 skip-if = appname == 'fennec' || os == "win" # http://bugs.python.org/issue14574
 
 [test_execute_sandboxes.py]
 [test_prefs.py]
 
 [test_shadow_dom.py]
-skip-if = stylo # Stylo doesn't support shadow DOM yet, bug 1293844
+skip-if = true # Bug 1293844, bug 1387678
 
 [test_chrome.py]
 skip-if = appname == 'fennec'
 
 [test_addons.py]
 skip-if = appname == 'fennec' # Bug 1330598
 
 [test_select.py]