diff -r 000000000000 -r 6474c204b198 browser/devtools/responsivedesign/test/browser_responsiveuiaddcustompreset.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/devtools/responsivedesign/test/browser_responsiveuiaddcustompreset.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,202 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+function test() {
+  let instance, deletedPresetA, deletedPresetB, oldPrompt;
+  let mgr = ResponsiveUI.ResponsiveUIManager;
+
+  waitForExplicitFinish();
+
+  gBrowser.selectedTab = gBrowser.addTab();
+  gBrowser.selectedBrowser.addEventListener("load", function onload() {
+    gBrowser.selectedBrowser.removeEventListener("load", onload, true);
+    waitForFocus(startTest, content);
+  }, true);
+
+  content.location = "data:text/html;charset=utf8,test custom presets in responsive mode";
+
+  // This test uses executeSoon() when responsive mode is initialized and when
+  // it is destroyed such that we get out of the init/destroy loops. If we try
+  // to init/destroy immediately, without waiting for the next loop, we get
+  // intermittent test failures.
+
+  function startTest() {
+    // Mocking prompt
+    oldPrompt = Services.prompt;
+    Services.prompt = {
+      value: "",
+      returnBool: true,
+      prompt: function(aParent, aDialogTitle, aText, aValue, aCheckMsg, aCheckState) {
+        aValue.value = this.value;
+        return this.returnBool;
+      }
+    };
+
+    registerCleanupFunction(() => Services.prompt = oldPrompt);
+
+    info("test started, waiting for responsive mode to activate");
+
+    document.getElementById("Tools:ResponsiveUI").removeAttribute("disabled");
+    mgr.once("on", onUIOpen);
+    synthesizeKeyFromKeyTag("key_responsiveUI");
+  }
+
+  function onUIOpen() {
+    // Is it open?
+    let container = gBrowser.getBrowserContainer();
+    is(container.getAttribute("responsivemode"), "true", "In responsive mode.");
+
+    instance = gBrowser.selectedTab.__responsiveUI;
+    ok(instance, "instance of the module is attached to the tab.");
+
+    instance.transitionsEnabled = false;
+
+    testAddCustomPreset();
+  }
+
+  function testAddCustomPreset() {
+    // Tries to add a custom preset and cancel the prompt
+    let idx = instance.menulist.selectedIndex;
+    let presetCount = instance.presets.length;
+
+    Services.prompt.value = "";
+    Services.prompt.returnBool = false;
+    instance.addbutton.doCommand();
+
+    is(idx, instance.menulist.selectedIndex, "selected item didn't change after add preset and cancel");
+    is(presetCount, instance.presets.length, "number of presets didn't change after add preset and cancel");
+
+    let customHeight = 123, customWidth = 456;
+    instance.setSize(customWidth, customHeight);
+
+    // Adds the custom preset with "Testing preset"
+    Services.prompt.value = "Testing preset";
+    Services.prompt.returnBool = true;
+    instance.addbutton.doCommand();
+
+    instance.menulist.selectedIndex = 1;
+
+    info("waiting for responsive mode to turn off");
+    mgr.once("off", restart);
+
+    // Force document reflow to avoid intermittent failures.
+    info("document height " + document.height);
+
+    // We're still in the loop of initializing the responsive mode.
+    // Let's wait next loop to stop it.
+    executeSoon(function() {
+      instance.close();
+    });
+  }
+
+  function restart() {
+    info("Restarting Responsive Mode");
+    mgr.once("on", function() {
+      let container = gBrowser.getBrowserContainer();
+      is(container.getAttribute("responsivemode"), "true", "In responsive mode.");
+
+      instance = gBrowser.selectedTab.__responsiveUI;
+
+      testCustomPresetInList();
+    });
+
+    // We're still in the loop of destroying the responsive mode.
+    // Let's wait next loop to start it.
+    executeSoon(function() {
+      synthesizeKeyFromKeyTag("key_responsiveUI");
+    });
+  }
+
+  function testCustomPresetInList() {
+    let customPresetIndex = getPresetIndex("456x123 (Testing preset)");
+    ok(customPresetIndex >= 0, "is the previously added preset (idx = " + customPresetIndex + ") in the list of items");
+
+    instance.menulist.selectedIndex = customPresetIndex;
+
+    is(content.innerWidth, 456, "add preset, and selected in the list, dimension valid (width)");
+    is(content.innerHeight, 123, "add preset, and selected in the list, dimension valid (height)");
+
+    testDeleteCustomPresets();
+  }
+
+  function testDeleteCustomPresets() {
+    instance.removebutton.doCommand();
+
+    instance.menulist.selectedIndex = 2;
+    deletedPresetA = instance.menulist.selectedItem.getAttribute("label");
+    instance.removebutton.doCommand();
+
+    instance.menulist.selectedIndex = 2;
+    deletedPresetB = instance.menulist.selectedItem.getAttribute("label");
+    instance.removebutton.doCommand();
+
+    info("waiting for responsive mode to turn off");
+    mgr.once("off", restartAgain);
+
+    // We're still in the loop of initializing the responsive mode.
+    // Let's wait next loop to stop it.
+    executeSoon(() => instance.close());
+  }
+
+  function restartAgain() {
+    info("waiting for responsive mode to turn on");
+    mgr.once("on", () => {
+      instance = gBrowser.selectedTab.__responsiveUI;
+      testCustomPresetsNotInListAnymore();
+    });
+
+    // We're still in the loop of destroying the responsive mode.
+    // Let's wait next loop to start it.
+    executeSoon(() => synthesizeKeyFromKeyTag("key_responsiveUI"));
+  }
+
+  function testCustomPresetsNotInListAnymore() {
+    let customPresetIndex = getPresetIndex(deletedPresetA);
+    is(customPresetIndex, -1, "deleted preset " + deletedPresetA + " is not in the list anymore");
+
+    customPresetIndex = getPresetIndex(deletedPresetB);
+    is(customPresetIndex, -1, "deleted preset " + deletedPresetB + " is not in the list anymore");
+
+    executeSoon(finishUp);
+  }
+
+  function finishUp() {
+    delete instance;
+    gBrowser.removeCurrentTab();
+
+    finish();
+  }
+
+  function getPresetIndex(presetLabel) {
+    function testOnePreset(c) {
+      if (c == 0) {
+        return -1;
+      }
+      instance.menulist.selectedIndex = c;
+
+      let item = instance.menulist.firstChild.childNodes[c];
+      if (item.getAttribute("label") === presetLabel) {
+        return c;
+      } else {
+        return testOnePreset(c - 1);
+      }
+    }
+    return testOnePreset(instance.menulist.firstChild.childNodes.length - 4);
+  }
+
+  function synthesizeKeyFromKeyTag(aKeyId) {
+    let key = document.getElementById(aKeyId);
+    isnot(key, null, "Successfully retrieved the <key> node");
+
+    let name = null;
+
+    if (key.getAttribute("keycode"))
+      name = key.getAttribute("keycode");
+    else if (key.getAttribute("key"))
+      name = key.getAttribute("key");
+
+    isnot(name, null, "Successfully retrieved keycode/key");
+
+    key.doCommand();
+  }
+}