Understanding JavaScript Testing
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This document discusses JavaScript testing and provides examples of writing tests and using testing frameworks like QUnit and JSUnit. It covers: - Why test JavaScript code due to cross-browser issues and bugs - Components of a test suite including tests, assertions, and a test runner - Examples of writing basic tests with assertions and handling asynchronous tests - Popular JavaScript testing frameworks like QUnit, JSUnit, YUITest
![Async Tests
(function(){
var queue = [], paused = false;
this.test = function(fn){
queue.push( fn );
runTest();
};
this.pause = function(){
paused = true;
};
this.resume = function(){
paused = false;
setTimeout(runTest, 1);
};
function runTest(){
if ( !paused && queue.length ) {
queue.shift()();
if ( !paused ) {
resume();
}
}
}
})();](https://image.slidesharecdn.com/js-testing-090916091841-phpapp01/85/Understanding-JavaScript-Testing-11-320.jpg)
![YUITest 2
YAHOO.example.yuitest.ArrayTestCase = new YAHOO.tool.TestCase({
name : "Array Tests",
setUp : function () {
this.data = [0,1,2,3,4]
},
tearDown : function () {
delete this.data;
},
testPop : function () {
var Assert = YAHOO.util.Assert;
var value = this.data.pop();
Assert.areEqual(4, this.data.length);
Assert.areEqual(4, value);
},
testPush : function () {
var Assert = YAHOO.util.Assert;
this.data.push(5);
Assert.areEqual(6, this.data.length);
Assert.areEqual(5, this.data[5]);
}
});](https://image.slidesharecdn.com/js-testing-090916091841-phpapp01/85/Understanding-JavaScript-Testing-23-320.jpg)
![Screw.Unit
describe("a nested describe", function() {
var invocations = [];
before(function() {
invocations.push("before");
});
describe("a doubly nested describe", function() {
before(function() {
invocations.push('inner before');
});
it("runs befores in all ancestors prior to an it", function() {
expect(invocations).to(equal, ["before", "inner before"]);
});
});
});](https://image.slidesharecdn.com/js-testing-090916091841-phpapp01/85/Understanding-JavaScript-Testing-29-320.jpg)
![JSSpec
describe('"Should have"s', {
'String length': function() {
expect("Hello").should_have(4, "characters");
},
'Array length': function() {
expect([1,2,3]).should_have(4, "items");
},
'Object's item length': function() {
expect({name:'Alan Kang', email:'jania902@gmail.com',
accounts:['A', 'B']}).should_have(3, "accounts");
},
'No match': function() {
expect("This is a string").should_have(5, "players");
},
'Exactly': function() {
expect([1,2,3]).should_have_exactly(2, "items");
},
'At least': function() {
expect([1,2,3]).should_have_at_least(4, "items");
},
'At most': function() {
expect([1,2,3]).should_have_at_most(2, "items");
}
})](https://image.slidesharecdn.com/js-testing-090916091841-phpapp01/85/Understanding-JavaScript-Testing-32-320.jpg)
![Env.js
$ java -jar build/js.jar
Rhino 1.6 release 6 2007 06 28
js> load('build/runtest/env.js');
js> window.location = 'test/index.html';
test/index.html
js> load('dist/jquery.js');
// Add pretty printing to jQuery objects:
js> jQuery.fn.toString = DOMNodeList.prototype.toString;
js> $('span').remove();
[ <span#å°åŒ—Taibei>, <span#å°åŒ—>, <span#utf8class1>,
<span#utf8class2>, <span#foo:bar>, <span#test.foo[5]bar> ]
// Yes - UTF-8 is supported in DOM documents!
js> $('span')
[ ]
js> $('div').append('<span><b>hello!</b> world</span>');
[ <div#main>, <div#foo> ]
js> $('span')
[ <span>, <span> ]
js> $('span').text()
hello! worldhello! world](https://image.slidesharecdn.com/js-testing-090916091841-phpapp01/85/Understanding-JavaScript-Testing-42-320.jpg)
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Understanding JavaScript Testing
- 1. JavaScript Testing John Resig http://ejohn.org/ - http://twitter.com/jeresig
- 2. Why Test JavaScript? ✦ Cross-browser issues. ✦ The possibility for causing an unforeseen problem is simply too great.
- 3. What should I use?
- 4. Looong Tail 250.0 187.5 125.0 62.5 0 Other
- 5. People don’t test. :-( 900 675 450 225 0 None
- 6. Basic Components ✦ Writing and understanding a JavaScript test suite is easy. ✦ Test Suite ✦ Tests ✦ Assertions ✦ Async Tests ✦ Test Runner
- 7. Assertions <html> <head> <title>Test Suite</title> <script> function assert( value, desc ) { var li = document.createElement("li"); li.className = value ? "pass" : "fail"; li.appendChild( document.createTextNode( desc ) ); document.getElementById("results").appendChild( li ); } window.onload = function(){ assert( true, "The test suite is running." ); }; </script> <style> #results li.pass { color: green; } #results li.fail { color: red; } </style> </head> <body> <ul id="results"></ul> </body> </html>
- 8. Tests test("A test.", function(){ assert( true, "First assertion completed" ); assert( true, "Second assertion completed" ); assert( true, "Third assertion completed" ); }); test("Another test.", function(){ assert( true, "First test completed" ); assert( false, "Second test failed" ); assert( true, "Third assertion completed" ); });
- 9. Tests var results; function assert( value, desc ) { var li = document.createElement("li"); li.className = value ? "pass" : "fail"; li.appendChild( document.createTextNode( desc ) ); results.appendChild( li ); if ( !value ) { li.parentNode.parentNode.className = "fail"; } return li; } function test(name, fn){ results = document.getElementById("results"); results = assert( true, name ).appendChild( document.createElement("ul") ); fn(); }
- 10. Async Tests test(function(){ pause(); setTimeout(function(){ assert( true, "First test completed" ); resume(); }, 100); }); test(function(){ pause(); setTimeout(function(){ assert( true, "Second test completed" ); resume(); }, 200); });
- 11. Async Tests (function(){ var queue = [], paused = false; this.test = function(fn){ queue.push( fn ); runTest(); }; this.pause = function(){ paused = true; }; this.resume = function(){ paused = false; setTimeout(runTest, 1); }; function runTest(){ if ( !paused && queue.length ) { queue.shift()(); if ( !paused ) { resume(); } } } })();
- 12. TestRunner ✦ Responsible for loading an executing tests. ✦ Sometimes individual test groups can run standalone (Dojo) sometimes they require the test runner (QUnit, JSUnit).
- 13. Popular Test Frameworks 250.0 187.5 125.0 62.5 0 QUnit JSUnit Selenium YUITest FireUnit Screw.Unit JSSpec
- 14. Unit Testing ✦ Break code into logical chucks for testing. ✦ Focus on one method at a time. ✦ Popular Frameworks: ✦ QUnit ✦ JSUnit ✦ YUITest
- 15. QUnit ✦ Unit Testing framework built for jQuery. ✦ Additional features: ✦ Supports asynchronous testing. ✦ Can break code into modules. ✦ Supports test timeouts. ✦ http://docs.jquery.com/QUnit
- 16. QUnit Style test("a basic test example", function() { ok( true, "this test is fine" ); var value = "hello"; equals( "hello", value, "We expect value to be hello" ); }); module("Module A"); test("first test within module", function() { ok( true, "all pass" ); }); test("second test within module", function() { ok( true, "all pass" ); }); module("Module B"); test("some other test", function() { expect(2); equals( true, false, "failing test" ); equals( true, true, "passing test" ); });
- 17. QUnit
- 18. JSUnit ✦ One of the oldest JavaScript testing frameworks. ✦ A port of JUnit to JavaScript, circa 2001. ✦ Code feels very 2001 (frames!) ✦ http://www.jsunit.net/
- 19. JSUnit function coreSuite() { var result = new top.jsUnitTestSuite(); result.addTestPage("tests/jsUnitAssertionTests.html"); result.addTestPage("tests/jsUnitSetUpTearDownTests.html"); result.addTestPage("tests/jsUnitRestoredHTMLDivTests.html"); result.addTestPage("tests/jsUnitFrameworkUtilityTests.html"); result.addTestPage("tests/jsUnitOnLoadTests.html"); result.addTestPage("tests/jsUnitUtilityTests.html"); return result; } function serverSuite() { var result = new top.jsUnitTestSuite(); result.addTestPage("tests/server/jsUnitVersionCheckTests.html"); result.addTestPage("tests/server/jsUnitServerAjaxTests.html"); return result; } function librariesSuite() { var result = new top.jsUnitTestSuite(); result.addTestPage("tests/jsUnitMockTimeoutTest.html"); return result; } function suite() { var newsuite = new top.jsUnitTestSuite(); newsuite.addTestSuite(coreSuite()); newsuite.addTestSuite(serverSuite()); newsuite.addTestSuite(librariesSuite()); return newsuite; }
- 20. JSUnit function testAssertNotUndefined() { assertNotUndefined("1 should not be undefined", 1); assertNotUndefined(1); } function testAssertNaN() { assertNaN("a string should not be a number", "string"); assertNaN("string"); } function testAssertNotNaN() { assertNotNaN("1 should not be not a number", 1); assertNotNaN(1); } function testFail() { var excep = null; try { fail("Failure message"); } catch (e) { excep = e; } assertJsUnitException("fail(string) should throw a JsUnitException", excep); } function testTooFewArguments() { var excep = null; try { assert(); } catch (e1) { excep = e1; } assertNonJsUnitException("Calling an assertion function with too few arguments should throw an exception", excep); }
- 21. JSUnit
- 22. YUITest (2 & 3) ✦ Testing framework built and developed by Yahoo (released Oct 2008). ✦ Completely overhauled to go with YUI v3. ✦ Features: ✦ Supports async tests. ✦ Has good event simulation. ✦ v2: http://developer.yahoo.com/yui/ examples/yuitest/ ✦ v3: http://developer.yahoo.com/yui/3/test/
- 23. YUITest 2 YAHOO.example.yuitest.ArrayTestCase = new YAHOO.tool.TestCase({ name : "Array Tests", setUp : function () { this.data = [0,1,2,3,4] }, tearDown : function () { delete this.data; }, testPop : function () { var Assert = YAHOO.util.Assert; var value = this.data.pop(); Assert.areEqual(4, this.data.length); Assert.areEqual(4, value); }, testPush : function () { var Assert = YAHOO.util.Assert; this.data.push(5); Assert.areEqual(6, this.data.length); Assert.areEqual(5, this.data[5]); } });
- 24. YUITest 2
- 25. YUITest 3 Y.example.test.DataTestCase = new Y.Test.Case({ name : "Data Tests", setUp : function () { this.data = { name: "test", year: 2007, beta: true }; }, tearDown : function () { delete this.data; }, testName : function () { var Assert = Y.Assert; Assert.isObject(this.data); Assert.isString(this.data.name); Assert.areEqual("test", this.data.name); }, testYear : function () { var Assert = Y.Assert; Assert.isObject(this.data); Assert.isNumber(this.data.year); Assert.areEqual(2007, this.data.year); } });
- 26. YUITest 3
- 27. Behavior Testing ✦ Similar to unit testing, but broken up by task. ✦ Functionally very similar to unit testing, uses different terminology ✦ Popular frameworks: ✦ Screw.Unit ✦ JSSpec
- 28. Screw.Unit ✦ Popular BDD framework. ✦ http://github.com/nathansobo/screw-unit/ tree/master
- 29. Screw.Unit describe("a nested describe", function() { var invocations = []; before(function() { invocations.push("before"); }); describe("a doubly nested describe", function() { before(function() { invocations.push('inner before'); }); it("runs befores in all ancestors prior to an it", function() { expect(invocations).to(equal, ["before", "inner before"]); }); }); });
- 30. Screw.Unit
- 31. JSSpec ✦ Used by MooTools as their testing framework. ✦ http://jania.pe.kr/aw/moin.cgi/JSSpec
- 32. JSSpec describe('"Should have"s', { 'String length': function() { expect("Hello").should_have(4, "characters"); }, 'Array length': function() { expect([1,2,3]).should_have(4, "items"); }, 'Object's item length': function() { expect({name:'Alan Kang', email:'[email protected]', accounts:['A', 'B']}).should_have(3, "accounts"); }, 'No match': function() { expect("This is a string").should_have(5, "players"); }, 'Exactly': function() { expect([1,2,3]).should_have_exactly(2, "items"); }, 'At least': function() { expect([1,2,3]).should_have_at_least(4, "items"); }, 'At most': function() { expect([1,2,3]).should_have_at_most(2, "items"); } })
- 33. JSSpec
- 34. Automation ✦ Functional Testing ✦ Browser launching ✦ Server-Side
- 35. Functional Testing ✦ Selenium IDE ✦ There may be others by Selenium is far and away the best.
- 36. Selenium IDE ✦ Records and automates actions performed by a user. ✦ An extension for Firefox that records the actions. ✦ Can play them back in all browsers (limited by cross-domain issues). ✦ Primarily for testing web applications - everyone should use it, though! ✦ http://seleniumhq.org/projects/ide/
- 37. Selenium IDE
- 38. Browser Launching ✦ Automates the process of opening browser windows, running tests, and getting results. ✦ Frequently require a specific framework. ✦ Popular frameworks: ✦ WebDriver http://code.google.com/p/ webdriver/ (Java) ✦ Waitr http://wtr.rubyforge.org/ (Ruby) ✦ JsTestDriver http://code.google.com/p/ js-test-driver/ (Java) ✦ Selenium RC http://seleniumhq.org/ projects/remote-control/ (Java)
- 40. Server-Side ✦ Ignore the browser! Simulate it on the server-side. ✦ Almost always uses Java + Rhino to construct a browser. ✦ Some frameworks: ✦ Crosscheck ✦ Env.js ✦ Blueridge
- 41. Server-Side ✦ Crosscheck ✦ Pure Java, even simulates browser bugs. ✦ http://www.thefrontside.net/crosscheck ✦ Env.js ✦ Pure JavaScript, focuses on standards support. ✦ http://github.com/thatcher/env-js/tree/ master ✦ Blueridge ✦ Env.js + Screw.Unit + Rhino ✦ http://github.com/relevance/blue-ridge/
- 42. Env.js $ java -jar build/js.jar Rhino 1.6 release 6 2007 06 28 js> load('build/runtest/env.js'); js> window.location = 'test/index.html'; test/index.html js> load('dist/jquery.js'); // Add pretty printing to jQuery objects: js> jQuery.fn.toString = DOMNodeList.prototype.toString; js> $('span').remove(); [ <span#å°åŒ—Taibei>, <span#å°åŒ—>, <span#utf8class1>, <span#utf8class2>, <span#foo:bar>, <span#test.foo[5]bar> ] // Yes - UTF-8 is supported in DOM documents! js> $('span') [ ] js> $('div').append('<span><b>hello!</b> world</span>'); [ <div#main>, <div#foo> ] js> $('span') [ <span>, <span> ] js> $('span').text() hello! worldhello! world
- 43. Distributed ✦ Selenium Grid ✦ Push Selenium tests out to many machines (that you manage), simultaneously. ✦ Collect and store the results. ✦ http://selenium-grid.seleniumhq.org/ ✦ TestSwarm ✦ Push tests to a distributed swarm of clients. ✦ Results viewable on the server. ✦ http://testswarm.com/
- 44. TestSwarm
- 46. Cost / Benefit IE 7 IE 6 FF 3 Safari 3 Opera 9.5 Cost Benefit Draw a line in the sand.
- 47. Graded Support Yahoo Browser Compatibility
- 48. Browser Support Grid IE Firefox Safari Opera Chrome Previous 6.0 2.0 3.0 9.5 Current 7.0 3.0 3.2 9.6 1.0 Next 8.0 3.1 4.0 10.0 2.0 jQuery Browser Support
- 49. Browser Support Grid IE Firefox Safari Opera Chrome Previous 6.0 2.0 3.0 9.5 Current 7.0 3.0 3.2 9.6 1.0 Next 8.0 3.1 4.0 10.0 2.0 jQuery 1.3 Browser Support
- 50. The Scaling Problem ✦ The Problem: ✦ jQuery has 6 test suites ✦ Run in 11 browsers ✦ (Not even including multiple platforms!) ✦ All need to be run for every commit, patch, and plugin. ✦ JavaScript testing doesn’t scale well.
- 51. Distributed Testing ✦ Hub server ✦ Clients connect and help run tests ✦ A simple JavaScript client that can be run in all browsers ✦ Including mobile browsers! ✦ TestSwarm
- 52. FF 3.5 FF 3.5 FF 3.5 IE 6 IE 6 FF 3 IE 6 Op 9 FF 3 IE 7 TestSwarm IE 7 Test Suite Test Suite Test Suite
- 53. Manual Testing ✦ Push tests to users who follow pre-defined steps ✦ Answer ‘Yes’/’No’ questions which are pushed back to the server. ✦ An effective way to distribute manual test load to dozens of clients.
- 54. TestSwarm.com ✦ Incentives for top testers (t-shirts, books) ✦ Will be opening for alpha testing very soon ✦ Help your favorite JavaScript library become better tested! ✦ http://testswarm.com
- 55. Questions ✦ Contact: ✦ John Resig ✦ http://ejohn.org/ ✦ http://twitter.com/jeresig ✦ More info: ✦ http://jsninja.com/Overview ✦ http://ejohn.org/blog/javascript-testing- does-not-scale/