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// Copyright 2008 The Closure Library Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS-IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
goog.provide('goog.ui.KeyboardShortcutHandlerTest');
goog.setTestOnly('goog.ui.KeyboardShortcutHandlerTest');
goog.require('goog.dom');
goog.require('goog.events');
goog.require('goog.events.BrowserEvent');
goog.require('goog.events.KeyCodes');
goog.require('goog.testing.MockClock');
goog.require('goog.testing.PropertyReplacer');
goog.require('goog.testing.StrictMock');
goog.require('goog.testing.events');
goog.require('goog.testing.jsunit');
goog.require('goog.ui.KeyboardShortcutHandler');
goog.require('goog.userAgent');
var Modifiers = goog.ui.KeyboardShortcutHandler.Modifiers;
var KeyCodes = goog.events.KeyCodes;
var handler;
var targetDiv;
var listener;
var mockClock;
var stubs = new goog.testing.PropertyReplacer();
/**
* Fires a keypress on the target div.
* @return {boolean} The returnValue of the sequence: false if
* preventDefault() was called on any of the events, true otherwise.
*/
function fire(keycode, opt_extraProperties, opt_element) {
return goog.testing.events.fireKeySequence(
opt_element || targetDiv, keycode, opt_extraProperties);
}
function fireAltGraphKey(keycode, keyPressKeyCode, opt_extraProperties,
opt_element) {
return goog.testing.events.fireNonAsciiKeySequence(
opt_element || targetDiv, keycode, keyPressKeyCode,
opt_extraProperties);
}
function setUp() {
targetDiv = goog.dom.getElement('targetDiv');
handler = new goog.ui.KeyboardShortcutHandler(
goog.dom.getElement('rootDiv'));
// Create a mock event listener in order to set expectations on what
// events are fired. We create a fake class whose only method is
// shortcutFired(shortcut identifier).
listener = new goog.testing.StrictMock(
{shortcutFired: goog.nullFunction});
goog.events.listen(
handler,
goog.ui.KeyboardShortcutHandler.EventType.SHORTCUT_TRIGGERED,
function(event) { listener.shortcutFired(event.identifier); });
// Set up a fake clock, because keyboard shortcuts *are* time
// sensitive.
mockClock = new goog.testing.MockClock(true);
}
function tearDown() {
mockClock.uninstall();
handler.dispose();
stubs.reset();
}
function testAllowsSingleLetterKeyBindingsSpecifiedAsString() {
listener.shortcutFired('lettergee');
listener.$replay();
handler.registerShortcut('lettergee', 'g');
fire(KeyCodes.G);
listener.$verify();
}
function testAllowsSingleLetterKeyBindingsSpecifiedAsKeyCode() {
listener.shortcutFired('lettergee');
listener.$replay();
handler.registerShortcut('lettergee', KeyCodes.G);
fire(KeyCodes.G);
listener.$verify();
}
function testDoesntFireWhenWrongKeyIsPressed() {
listener.$replay(); // no events expected
handler.registerShortcut('letterjay', 'j');
fire(KeyCodes.G);
listener.$verify();
}
function testAllowsControlAndLetterSpecifiedAsAString() {
listener.shortcutFired('lettergee');
listener.$replay();
handler.registerShortcut('lettergee', 'ctrl+g');
fire(KeyCodes.G, {ctrlKey: true});
listener.$verify();
}
function testAllowsControlAndLetterSpecifiedAsArgSequence() {
listener.shortcutFired('lettergeectrl');
listener.$replay();
handler.registerShortcut('lettergeectrl',
KeyCodes.G, Modifiers.CTRL);
fire(KeyCodes.G, {ctrlKey: true});
listener.$verify();
}
function testAllowsControlAndLetterSpecifiedAsArray() {
listener.shortcutFired('lettergeectrl');
listener.$replay();
handler.registerShortcut('lettergeectrl',
[KeyCodes.G, Modifiers.CTRL]);
fire(KeyCodes.G, {ctrlKey: true});
listener.$verify();
}
function testAllowsShift() {
listener.shortcutFired('lettergeeshift');
listener.$replay();
handler.registerShortcut('lettergeeshift',
[KeyCodes.G, Modifiers.SHIFT]);
fire(KeyCodes.G, {shiftKey: true});
listener.$verify();
}
function testAllowsAlt() {
listener.shortcutFired('lettergeealt');
listener.$replay();
handler.registerShortcut('lettergeealt',
[KeyCodes.G, Modifiers.ALT]);
fire(KeyCodes.G, {altKey: true});
listener.$verify();
}
function testAllowsMeta() {
listener.shortcutFired('lettergeemeta');
listener.$replay();
handler.registerShortcut('lettergeemeta',
[KeyCodes.G, Modifiers.META]);
fire(KeyCodes.G, {metaKey: true});
listener.$verify();
}
function testAllowsMultipleModifiers() {
listener.shortcutFired('lettergeectrlaltshift');
listener.$replay();
handler.registerShortcut('lettergeectrlaltshift',
KeyCodes.G, Modifiers.CTRL | Modifiers.ALT | Modifiers.SHIFT);
fire(KeyCodes.G, {ctrlKey: true, altKey: true, shiftKey: true});
listener.$verify();
}
function testAllowsMultipleModifiersSpecifiedAsString() {
listener.shortcutFired('lettergeectrlaltshiftmeta');
listener.$replay();
handler.registerShortcut('lettergeectrlaltshiftmeta',
'ctrl+shift+alt+meta+g');
fire(KeyCodes.G,
{ctrlKey: true, altKey: true, shiftKey: true, metaKey: true});
listener.$verify();
}
function testPreventsDefaultOnReturnFalse() {
listener.shortcutFired('x');
listener.$replay();
handler.registerShortcut('x', 'x');
var key = goog.events.listen(handler,
goog.ui.KeyboardShortcutHandler.EventType.SHORTCUT_TRIGGERED,
function(event) { return false });
assertFalse('return false in listener must prevent default',
fire(KeyCodes.X));
listener.$verify();
goog.events.unlistenByKey(key);
}
function testPreventsDefaultWhenExceptionThrown() {
handler.registerShortcut('x', 'x');
handler.setAlwaysPreventDefault(true);
goog.events.listenOnce(handler,
goog.ui.KeyboardShortcutHandler.EventType.SHORTCUT_TRIGGERED,
function(event) { throw new Error('x'); });
// We can't use the standard infrastructure to detect that
// the event was preventDefaulted, because of the exception.
var callCount = 0;
stubs.set(goog.events.BrowserEvent.prototype, 'preventDefault',
function() {
callCount++;
});
var e = assertThrows(goog.partial(fire, KeyCodes.X));
assertEquals('x', e.message);
assertEquals(1, callCount);
}
function testDoesntFireWhenUserForgetsRequiredModifier() {
listener.$replay(); // no events expected
handler.registerShortcut('lettergeectrl',
KeyCodes.G, Modifiers.CTRL);
fire(KeyCodes.G);
listener.$verify();
}
function testDoesntFireIfTooManyModifiersPressed() {
listener.$replay(); // no events expected
handler.registerShortcut('lettergeectrl',
KeyCodes.G, Modifiers.CTRL);
fire(KeyCodes.G, {ctrlKey: true, metaKey: true});
listener.$verify();
}
function testDoesntFireIfAnyRequiredModifierForgotten() {
listener.$replay(); // no events expected
handler.registerShortcut('lettergeectrlaltshift',
KeyCodes.G, Modifiers.CTRL | Modifiers.ALT | Modifiers.SHIFT);
fire(KeyCodes.G, {altKey: true, shiftKey: true});
listener.$verify();
}
function testAllowsMultiKeySequenceSpecifiedAsArray() {
listener.shortcutFired('quitemacs');
listener.$replay();
handler.registerShortcut('quitemacs',
[KeyCodes.X, Modifiers.CTRL,
KeyCodes.C]);
assertFalse(fire(KeyCodes.X, {ctrlKey: true}));
fire(KeyCodes.C);
listener.$verify();
}
function testAllowsMultiKeySequenceSpecifiedAsArguments() {
listener.shortcutFired('quitvi');
listener.$replay();
handler.registerShortcut('quitvi',
KeyCodes.SEMICOLON, Modifiers.SHIFT,
KeyCodes.Q, Modifiers.NONE,
KeyCodes.NUM_ONE, Modifiers.SHIFT);
var shiftProperties = { shiftKey: true };
assertFalse(fire(KeyCodes.SEMICOLON, shiftProperties));
assertFalse(fire(KeyCodes.Q));
fire(KeyCodes.NUM_ONE, shiftProperties);
listener.$verify();
}
function testMultiKeyEventIsNotFiredIfUserIsTooSlow() {
listener.$replay(); // no events expected
handler.registerShortcut('quitemacs',
[KeyCodes.X, Modifiers.CTRL,
KeyCodes.C]);
fire(KeyCodes.X, {ctrlKey: true});
// Wait 3 seconds before hitting C. Although the actual limit is 1500
// at time of writing, it's best not to over-specify functionality.
mockClock.tick(3000);
fire(KeyCodes.C);
listener.$verify();
}
function testAllowsMultipleAHandlers() {
listener.shortcutFired('quitvi');
listener.shortcutFired('letterex');
listener.shortcutFired('quitemacs');
listener.$replay();
// register 3 handlers in 3 diferent ways
handler.registerShortcut('quitvi',
KeyCodes.SEMICOLON, Modifiers.SHIFT,
KeyCodes.Q, Modifiers.NONE,
KeyCodes.NUM_ONE, Modifiers.SHIFT);
handler.registerShortcut('quitemacs',
[KeyCodes.X, Modifiers.CTRL,
KeyCodes.C]);
handler.registerShortcut('letterex', 'x');
// quit vi
var shiftProperties = { shiftKey: true };
fire(KeyCodes.SEMICOLON, shiftProperties);
fire(KeyCodes.Q);
fire(KeyCodes.NUM_ONE, shiftProperties);
// then press the letter x
fire(KeyCodes.X);
// then quit emacs
fire(KeyCodes.X, {ctrlKey: true});
fire(KeyCodes.C);
listener.$verify();
}
function testCanRemoveOneHandler() {
listener.shortcutFired('letterex');
listener.$replay();
// register 2 handlers, then remove quitvi
handler.registerShortcut('quitvi',
KeyCodes.COLON, Modifiers.NONE,
KeyCodes.Q, Modifiers.NONE,
KeyCodes.EXCLAMATION, Modifiers.NONE);
handler.registerShortcut('letterex', 'x');
handler.unregisterShortcut(
KeyCodes.COLON, Modifiers.NONE,
KeyCodes.Q, Modifiers.NONE,
KeyCodes.EXCLAMATION, Modifiers.NONE);
// call the "quit VI" keycodes, even though it is removed
fire(KeyCodes.COLON);
fire(KeyCodes.Q);
fire(KeyCodes.EXCLAMATION);
// press the letter x
fire(KeyCodes.X);
listener.$verify();
}
function testCanRemoveTwoHandlers() {
listener.$replay(); // no events expected
handler.registerShortcut('quitemacs',
[KeyCodes.X, Modifiers.CTRL,
KeyCodes.C]);
handler.registerShortcut('letterex', 'x');
handler.unregisterShortcut(
[KeyCodes.X, Modifiers.CTRL,
KeyCodes.C]);
handler.unregisterShortcut('x');
fire(KeyCodes.X, {ctrlKey: true});
fire(KeyCodes.C);
fire(KeyCodes.X);
listener.$verify();
}
function testIsShortcutRegistered_single() {
assertFalse(handler.isShortcutRegistered('x'));
handler.registerShortcut('letterex', 'x');
assertTrue(handler.isShortcutRegistered('x'));
handler.unregisterShortcut('x');
assertFalse(handler.isShortcutRegistered('x'));
}
function testIsShortcutRegistered_multi() {
assertFalse(handler.isShortcutRegistered('a'));
assertFalse(handler.isShortcutRegistered('a b'));
assertFalse(handler.isShortcutRegistered('a b c'));
handler.registerShortcut('ab', 'a b');
assertFalse(handler.isShortcutRegistered('a'));
assertTrue(handler.isShortcutRegistered('a b'));
assertFalse(handler.isShortcutRegistered('a b c'));
handler.unregisterShortcut('a b');
assertFalse(handler.isShortcutRegistered('a'));
assertFalse(handler.isShortcutRegistered('a b'));
assertFalse(handler.isShortcutRegistered('a b c'));
}
function testUnregister_subsequence() {
// Unregistering a partial sequence should not orphan shortcuts further in the
// sequence.
handler.registerShortcut('abc', 'a b c');
handler.unregisterShortcut('a b');
assertTrue(handler.isShortcutRegistered('a b c'));
}
function testUnregister_supersequence() {
// Unregistering a sequence that extends beyond a registered sequence should
// do nothing.
handler.registerShortcut('ab', 'a b');
handler.unregisterShortcut('a b c');
assertTrue(handler.isShortcutRegistered('a b'));
}
function testUnregister_partialMatchSequence() {
// Unregistering a sequence that partially matches a registered sequence
// should do nothing.
handler.registerShortcut('abc', 'a b c');
handler.unregisterShortcut('a b x');
assertTrue(handler.isShortcutRegistered('a b c'));
}
function testUnregister_deadBranch() {
// Unregistering a sequence should prune any dead branches in the tree.
handler.registerShortcut('abc', 'a b c');
handler.unregisterShortcut('a b c');
// Default is not should not be prevented in the A key stroke because the A
// branch has been removed from the tree.
assertTrue(fire(KeyCodes.A));
}
/**
* Registers a slew of keyboard shortcuts to test each primary category
* of shortcuts.
*/
function registerEnterSpaceXF1AltY() {
// Enter and space are specially handled keys.
handler.registerShortcut('enter', KeyCodes.ENTER);
handler.registerShortcut('space', KeyCodes.SPACE);
// 'x' should be treated as text in many contexts
handler.registerShortcut('x', 'x');
// F1 is a global shortcut.
handler.registerShortcut('global', KeyCodes.F1);
// Alt-Y has modifiers, which pass through most form elements.
handler.registerShortcut('withAlt', 'alt+y');
}
/**
* Fires enter, space, X, F1, and Alt-Y keys on a widget.
* @param {Element} target The element on which to fire the events.
*/
function fireEnterSpaceXF1AltY(target) {
fire(KeyCodes.ENTER, undefined, target);
fire(KeyCodes.SPACE, undefined, target);
fire(KeyCodes.X, undefined, target);
fire(KeyCodes.F1, undefined, target);
fire(KeyCodes.Y, {altKey: true}, target);
}
function testIgnoreNonGlobalShortcutsInSelect() {
var targetSelect = goog.dom.getElement('targetSelect');
listener.shortcutFired('global');
listener.shortcutFired('withAlt');
listener.$replay();
registerEnterSpaceXF1AltY();
fireEnterSpaceXF1AltY(goog.dom.getElement('targetSelect'));
listener.$verify();
}
function testIgnoreNonGlobalShortcutsInTextArea() {
listener.shortcutFired('global');
listener.shortcutFired('withAlt');
listener.$replay();
registerEnterSpaceXF1AltY();
fireEnterSpaceXF1AltY(goog.dom.getElement('targetTextArea'));
listener.$verify();
}
/**
* Checks that the shortcuts are fired on each target.
* @param {Array<string>} shortcuts A list of shortcut identifiers.
* @param {Array<string>} targets A list of element IDs.
* @param {function(Element)} fireEvents Function that fires events.
*/
function expectShortcutsOnTargets(shortcuts, targets, fireEvents) {
for (var i = 0, ii = targets.length; i < ii; i++) {
for (var j = 0, jj = shortcuts.length; j < jj; j++) {
listener.shortcutFired(shortcuts[j]);
}
listener.$replay();
fireEvents(goog.dom.getElement(targets[i]));
listener.$verify();
listener.$reset();
}
}
function testIgnoreShortcutsExceptEnterInTextInputFields() {
var targets = [
'targetColor',
'targetDate',
'targetDateTime',
'targetDateTimeLocal',
'targetEmail',
'targetMonth',
'targetNumber',
'targetPassword',
'targetSearch',
'targetTel',
'targetText',
'targetTime',
'targetUrl',
'targetWeek'
];
registerEnterSpaceXF1AltY();
expectShortcutsOnTargets(
['enter', 'global', 'withAlt'], targets, fireEnterSpaceXF1AltY);
}
function testIgnoreSpaceInCheckBoxAndButton() {
registerEnterSpaceXF1AltY();
expectShortcutsOnTargets(
['enter', 'x', 'global', 'withAlt'],
['targetCheckBox', 'targetButton'],
fireEnterSpaceXF1AltY);
}
function testIgnoreNonGlobalShortcutsInContentEditable() {
// Don't set design mode in later IE as javascripts don't run when in
// that mode.
var setDesignMode = !goog.userAgent.IE ||
!goog.userAgent.isVersionOrHigher('9');
try {
if (setDesignMode) {
document.designMode = 'on';
}
targetDiv.contentEditable = 'true';
// Expect only global shortcuts.
listener.shortcutFired('global');
listener.$replay();
registerEnterSpaceXF1AltY();
fireEnterSpaceXF1AltY(targetDiv);
listener.$verify();
} finally {
if (setDesignMode) {
document.designMode = 'off';
}
targetDiv.contentEditable = 'false';
}
}
function testSetAllShortcutsAreGlobal() {
handler.setAllShortcutsAreGlobal(true);
registerEnterSpaceXF1AltY();
expectShortcutsOnTargets(
['enter', 'space', 'x', 'global', 'withAlt'], ['targetTextArea'],
fireEnterSpaceXF1AltY);
}
function testSetModifierShortcutsAreGlobalFalse() {
handler.setModifierShortcutsAreGlobal(false);
registerEnterSpaceXF1AltY();
expectShortcutsOnTargets(
['global'], ['targetTextArea'], fireEnterSpaceXF1AltY);
}
function testAltGraphKeyOnUSLayout() {
// Windows does not assign printable characters to any ctrl+alt keys of
// the US layout. This test verifies we fire shortcut events when typing
// ctrl+alt keys on the US layout.
listener.shortcutFired('letterOne');
listener.shortcutFired('letterTwo');
listener.shortcutFired('letterThree');
listener.shortcutFired('letterFour');
listener.shortcutFired('letterFive');
if (goog.userAgent.WINDOWS && !goog.userAgent.GECKO) {
listener.$replay();
handler.registerShortcut('letterOne', 'ctrl+alt+1');
handler.registerShortcut('letterTwo', 'ctrl+alt+2');
handler.registerShortcut('letterThree', 'ctrl+alt+3');
handler.registerShortcut('letterFour', 'ctrl+alt+4');
handler.registerShortcut('letterFive', 'ctrl+alt+5');
// Send key events on the English (United States) layout.
fireAltGraphKey(KeyCodes.ONE, 0, {ctrlKey: true, altKey: true});
fireAltGraphKey(KeyCodes.TWO, 0, {ctrlKey: true, altKey: true});
fireAltGraphKey(KeyCodes.THREE, 0, {ctrlKey: true, altKey: true});
fireAltGraphKey(KeyCodes.FOUR, 0, {ctrlKey: true, altKey: true});
fireAltGraphKey(KeyCodes.FIVE, 0, {ctrlKey: true, altKey: true});
listener.$verify();
}
}
function testAltGraphKeyOnFrenchLayout() {
// Windows assigns printable characters to ctrl+alt+[2-5] keys of the
// French layout. This test verifies we fire shortcut events only when
// we type ctrl+alt+1 keys on the French layout.
listener.shortcutFired('letterOne');
if (goog.userAgent.WINDOWS && !goog.userAgent.GECKO) {
listener.$replay();
handler.registerShortcut('letterOne', 'ctrl+alt+1');
handler.registerShortcut('letterTwo', 'ctrl+alt+2');
handler.registerShortcut('letterThree', 'ctrl+alt+3');
handler.registerShortcut('letterFour', 'ctrl+alt+4');
handler.registerShortcut('letterFive', 'ctrl+alt+5');
// Send key events on the French (France) layout.
fireAltGraphKey(KeyCodes.ONE, 0, {ctrlKey: true, altKey: true});
fireAltGraphKey(KeyCodes.TWO, 0x0303, {ctrlKey: true, altKey: true});
fireAltGraphKey(KeyCodes.THREE, 0x0023, {ctrlKey: true, altKey: true});
fireAltGraphKey(KeyCodes.FOUR, 0x007b, {ctrlKey: true, altKey: true});
fireAltGraphKey(KeyCodes.FIVE, 0x205b, {ctrlKey: true, altKey: true});
listener.$verify();
}
}
function testAltGraphKeyOnSpanishLayout() {
// Windows assigns printable characters to ctrl+alt+[1-5] keys of the
// Spanish layout. This test verifies we do not fire shortcut events at
// all when typing ctrl+alt+[1-5] keys on the Spanish layout.
if (goog.userAgent.WINDOWS && !goog.userAgent.GECKO) {
listener.$replay();
handler.registerShortcut('letterOne', 'ctrl+alt+1');
handler.registerShortcut('letterTwo', 'ctrl+alt+2');
handler.registerShortcut('letterThree', 'ctrl+alt+3');
handler.registerShortcut('letterFour', 'ctrl+alt+4');
handler.registerShortcut('letterFive', 'ctrl+alt+5');
// Send key events on the Spanish (Spain) layout.
fireAltGraphKey(KeyCodes.ONE, 0x007c, {ctrlKey: true, altKey: true});
fireAltGraphKey(KeyCodes.TWO, 0x0040, {ctrlKey: true, altKey: true});
fireAltGraphKey(KeyCodes.THREE, 0x0023, {ctrlKey: true, altKey: true});
fireAltGraphKey(KeyCodes.FOUR, 0x0303, {ctrlKey: true, altKey: true});
fireAltGraphKey(KeyCodes.FIVE, 0x20ac, {ctrlKey: true, altKey: true});
listener.$verify();
}
}
function testNumpadKeyShortcuts() {
var testCases = [
['letterNumpad0', 'num-0', KeyCodes.NUM_ZERO],
['letterNumpad1', 'num-1', KeyCodes.NUM_ONE],
['letterNumpad2', 'num-2', KeyCodes.NUM_TWO],
['letterNumpad3', 'num-3', KeyCodes.NUM_THREE],
['letterNumpad4', 'num-4', KeyCodes.NUM_FOUR],
['letterNumpad5', 'num-5', KeyCodes.NUM_FIVE],
['letterNumpad6', 'num-6', KeyCodes.NUM_SIX],
['letterNumpad7', 'num-7', KeyCodes.NUM_SEVEN],
['letterNumpad8', 'num-8', KeyCodes.NUM_EIGHT],
['letterNumpad9', 'num-9', KeyCodes.NUM_NINE],
['letterNumpadMultiply', 'num-multiply', KeyCodes.NUM_MULTIPLY],
['letterNumpadPlus', 'num-plus', KeyCodes.NUM_PLUS],
['letterNumpadMinus', 'num-minus', KeyCodes.NUM_MINUS],
['letterNumpadPERIOD', 'num-period', KeyCodes.NUM_PERIOD],
['letterNumpadDIVISION', 'num-division', KeyCodes.NUM_DIVISION]
];
for (var i = 0; i < testCases.length; ++i) {
listener.shortcutFired(testCases[i][0]);
}
listener.$replay();
// Register shortcuts for numpad keys and send numpad-key events.
for (var i = 0; i < testCases.length; ++i) {
handler.registerShortcut(testCases[i][0], testCases[i][1]);
fire(testCases[i][2]);
}
listener.$verify();
}
function testGeckoShortcuts() {
listener.shortcutFired('1');
listener.$replay();
handler.registerShortcut('1', 'semicolon');
if (goog.userAgent.GECKO) {
fire(goog.events.KeyCodes.FF_SEMICOLON);
} else {
fire(goog.events.KeyCodes.SEMICOLON);
}
listener.$verify();
}
function testRegisterShortcut_modifierOnly() {
assertThrows('Registering a shortcut with just modifiers should fail.',
goog.bind(handler.registerShortcut, handler, 'name', 'Shift'));
}
function testParseStringShortcut_unknownKey() {
assertThrows('Unknown keys should fail.', goog.bind(
goog.ui.KeyboardShortcutHandler.parseStringShortcut, null, 'NotAKey'));
}
// Regression test for failure to reset keyCode between strokes.
function testParseStringShortcut_resetKeyCode() {
var strokes = goog.ui.KeyboardShortcutHandler.parseStringShortcut('A Shift');
assertNull('The second stroke only has a modifier key.', strokes[1].keyCode);
}