1 files changed, 69 insertions, 0 deletions
diff --git a/modules/libpref/test/unit/test_dirtyPrefs.js b/modules/libpref/test/unit/test_dirtyPrefs.js
new file mode 100644
index 0000000000..e107bef363
--- /dev/null
+++ b/modules/libpref/test/unit/test_dirtyPrefs.js
@@ -0,0 +1,69 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* Tests for handling of the preferences 'dirty' flag (bug 985998) */
+
+function run_test() {
+  const ps = Services.prefs;
+
+  let defaultBranch = ps.getDefaultBranch("");
+  let userBranch = ps.getBranch("");
+
+  let prefFile = do_get_profile();
+  prefFile.append("prefs.js");
+
+  //* *************************************************************************//
+  // prefs are not dirty after a write
+  ps.savePrefFile(null);
+  Assert.ok(!ps.dirty);
+
+  // set a new a user value, we should become dirty
+  userBranch.setBoolPref("DirtyTest.new.bool", true);
+  Assert.ok(ps.dirty);
+  ps.savePrefFile(null);
+  // Overwrite a pref with the same value => not dirty
+  userBranch.setBoolPref("DirtyTest.new.bool", true);
+  Assert.ok(!ps.dirty);
+
+  // Repeat for the other two types
+  userBranch.setIntPref("DirtyTest.new.int", 1);
+  Assert.ok(ps.dirty);
+  ps.savePrefFile(null);
+  // Overwrite a pref with the same value => not dirty
+  userBranch.setIntPref("DirtyTest.new.int", 1);
+  Assert.ok(!ps.dirty);
+
+  userBranch.setCharPref("DirtyTest.new.char", "oop");
+  Assert.ok(ps.dirty);
+  ps.savePrefFile(null);
+  // Overwrite a pref with the same value => not dirty
+  userBranch.setCharPref("DirtyTest.new.char", "oop");
+  Assert.ok(!ps.dirty);
+
+  // change *type* of a user value -> dirty
+  userBranch.setBoolPref("DirtyTest.new.char", false);
+  Assert.ok(ps.dirty);
+  ps.savePrefFile(null);
+
+  // Set a default pref => not dirty (defaults don't go into prefs.js)
+  defaultBranch.setBoolPref("DirtyTest.existing.bool", true);
+  Assert.ok(!ps.dirty);
+  // Fail to change type of a pref with default value -> not dirty
+  do_check_throws(function () {
+    userBranch.setCharPref("DirtyTest.existing.bool", "boo");
+  }, Cr.NS_ERROR_UNEXPECTED);
+  Assert.ok(!ps.dirty);
+
+  // Set user value same as default, not dirty
+  userBranch.setBoolPref("DirtyTest.existing.bool", true);
+  Assert.ok(!ps.dirty);
+  // User value different from default, dirty
+  userBranch.setBoolPref("DirtyTest.existing.bool", false);
+  Assert.ok(ps.dirty);
+  ps.savePrefFile(null);
+  // Back to default value, dirty again
+  userBranch.setBoolPref("DirtyTest.existing.bool", true);
+  Assert.ok(ps.dirty);
+  ps.savePrefFile(null);
+}