Bug 1317270 - Allow to set preference values on the default branch. r=maja_zf

MozReview-Commit-ID: BOUMMmmGwrX

--HG--
extra : rebase_source : d3f2adf80511835ed7673b44540c66c43175c3cc

testing/firefox-ui/tests/puppeteer/test_prefs.py

@@ -145,3 +145,21 @@ class testPreferences(PuppeteerMixin, MarionetteTestCase):
         # Remove when all self.marionette methods are implemented
         # Please see Bug 1293588
         self.marionette.clear_pref(self.string_pref)
+
+    def test_set_pref_default_branch(self):
+        orig_value = self.puppeteer.prefs.get_pref(self.string_pref, default_branch=True)
+
+        try:
+            self.puppeteer.prefs.set_pref(self.string_pref, 'default', default_branch=True)
+            self.assertEqual(self.puppeteer.prefs.get_pref(self.string_pref), 'default')
+
+            self.puppeteer.prefs.set_pref(self.string_pref, 'user')
+            self.assertEqual(self.puppeteer.prefs.get_pref(self.string_pref), 'user')
+            self.assertEqual(self.puppeteer.prefs.get_pref(self.string_pref, default_branch=True),
+                             'default')
+
+            self.marionette.clear_pref(self.string_pref)
+            self.assertEqual(self.puppeteer.prefs.get_pref(self.string_pref), 'default')
+
+        finally:
+            self.puppeteer.prefs.set_pref(self.string_pref, orig_value, default_branch=True)

testing/puppeteer/firefox/firefox_puppeteer/api/prefs.py

@@ -100,7 +100,7 @@ class Preferences(BaseLib):
               }
             """, script_args=[pref_name])
 
-    def set_pref(self, pref_name, value):
+    def set_pref(self, pref_name, value, default_branch=False):
         """Sets a preference to a specified value.
 
         To set the value of a preference its name has to be specified.
@@ -111,6 +111,9 @@ class Preferences(BaseLib):
 
         :param pref_name: The preference to set
         :param value: The value to set the preference to
+        :param default_branch: Optional, flag to use the default branch,
+         default to `False`
+
         """
         assert pref_name is not None
         assert value is not None
@@ -122,10 +125,16 @@ class Preferences(BaseLib):
 
             retval = self.marionette.execute_script("""
               Components.utils.import("resource://gre/modules/Services.jsm");
-              let prefBranch = Services.prefs;
 
-              let pref_name = arguments[0];
-              let value = arguments[1];
+              let [pref_name, value, default_branch] = arguments;
+
+              let prefBranch;
+              if (default_branch) {
+                prefBranch = Services.prefs.getDefaultBranch("");
+              }
+              else {
+                prefBranch = Services.prefs;
+              }
 
               let type = prefBranch.getPrefType(pref_name);
 
@@ -161,6 +170,6 @@ class Preferences(BaseLib):
               }
 
               return true;
-            """, script_args=[pref_name, value])
+            """, script_args=[pref_name, value, default_branch])
 
         assert retval