JavaScript是一门脚本语言，并不包含编译器，所以无法保证类型安全。
单元测试可以弥补编译器的缺乏，找出潜在的缺陷。
1 Jasmine测试框架
Jasmine是一种测试框架，定义了测试用例的语法、API、如何编写断言等等。类似的产品还包括Mocha等。
call browser-visit-direct.html # windows
open browser-visit-direct.html # osx
或者直接用浏览器打开browser-visit-direct.html:
<html>
<head>
<link rel="stylesheet" type="text/css" href="https://cdnjs.cloudflare.com/ajax/libs/jasmine/2.3.3/jasmine.min.css">
<script src="https://cdnjs.cloudflare.com/ajax/libs/jasmine/2.3.3/jasmine.min.js"></script>
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/jasmine/2.3.3/jasmine-html.min.js"></script>
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/jasmine/2.3.3/boot.min.js"></script>
</head>
<body>
</body>
<script type="text/javascript">
var calculator = {
sum: function(x, y) {
return x + y;
}
}
// Paste in the test code here.
describe('calculator', function () {
it('1 + 1 should equal 2'); //没有添加测试的主体，因此状态上方显示的是pending
it('1 + 1 should equal 2', function() {
expect(1 + 1).toBe(1);
});
it('1 + 1 should equal 2', function() {
expect(1 + 1).toBe(2);
});
it('1 + 1 should equal 2', function () {
expect(calculator.sum(1, 1)).toBe(2);
});
});
it('others', function(){
expect(true).toBe(true);
expect(false).not.toBe(true);
expect(1).toEqual(1);
expect('foo').toEqual('foo');
expect('foo').not.toEqual('bar');
})
</script>
</html>
可以看到
其中，测试中的首句describe可以理解为包含多个测试样例的容器。
it是单元测试的核心代码，我们在it块内调用函数，检查返回值是否符合预期。每个expect语句都接受一个参数，根据内置的匹配函数或者自定义匹配函数进行判断。
常用的Jasmine匹配函数包括：
- toEqual
- toBe
- toBeTruthy
- toBeFalsy
……
2 Karma安装和配置
1、install nodejs： https://nodejs.org/en/
2、淘宝cnpm：https://npm.taobao.org/
查看全局安装的模块：cnpm list -g
3、安装karma
$ cnpm install -g karma-cli # 为了能在命令行直接执行 karma 命令
$ mkdir ex03 & cd ex03
$ cnpm install karma --save-dev # 自动生成package.json
$ cnpm install karma-jasmine karma-chrome-launcher --save-dev
$ cat package.json
{
"devDependencies": {
"karma": "^1.7.1",
"karma-chrome-launcher": "^2.2.0",
"karma-jasmine": "^1.1.0"
}
}
$ karma init # 交互式自动生成karma.conf.js
3 单元测试
3.1 编写
// File: ex03/controller.js
angular.module('notesApp', [])
.controller('ListCtrl', [function() {
var self = this;
self.items = [
{id: 1, label: 'First', done: true},
{id: 2, label: 'Second', done: false}
];
self.getDoneClass = function(item) {
return {
finished: item.done,
unfinished: !item.done
};
};
}]);
// File: ex03/controllerSpec.js
describe('Controller: ListCtrl', function() {
// Instantiate a new version of my module before each test
beforeEach(module('notesApp'));
var ctrl;
// Before each unit test, instantiate a new instance
// of the controller
beforeEach(inject(function($controller) {
ctrl = $controller('ListCtrl');
}));
it('should have items available on load', function() {
expect(ctrl.items).toEqual([
{id: 1, label: 'First', done: true},
{id: 2, label: 'Second', done: false}
]);
});
it('should have highlight items based on state', function() {
var item = {id: 1, label: 'First', done: true};
var actualClass = ctrl.getDoneClass(item);
expect(actualClass.finished).toBeTruthy();
expect(actualClass.unfinished).toBeFalsy();
item.done = false;
actualClass = ctrl.getDoneClass(item);
expect(actualClass.finished).toBeFalsy();
expect(actualClass.unfinished).toBeTruthy();
});
});
karma.conf.js中，files包含需要引入的js文件，browser表示要启动的浏览器
// list of files / patterns to load in the browser
files: [
'angular.min.js',
'angular-mocks.js',
'controller.js',
'controllerSpec.js'
],
// Start these browsers, currently available:
// - Chrome
// - ChromeCanary
// - Firefox
// - Opera
// - Safari (only Mac)
// - PhantomJS
// - IE (only Windows)
browsers: ['Chrome'],
3.2 运行
$ karma start
11 11 2017 10:29:41.138:WARN [karma]: No captured browser, open http://localhost:8080/
11 11 2017 10:29:41.152:INFO [karma]: Karma v1.7.1 server started at http://0.0.0.0:8080/
11 11 2017 10:29:41.153:INFO [launcher]: Launching browser Chrome with unlimited concurrency
11 11 2017 10:29:41.166:INFO [launcher]: Starting browser Chrome
11 11 2017 10:29:43.146:INFO [Chrome 62.0.3202 (Windows 10 0.0.0)]: Connected on socket Yi2gR771fEmcfPqnAAAA with id 31405350
Chrome 62.0.3202 (Windows 10 0.0.0): Executed 2 of 2 SUCCESS (0.032 secs / 0.022 secs)
源码：https://github.com/shenjiefeng/js-fortest/tree/master/angularjs/ex04-unittest/
3.3 使用PhantomJS
phantomjs是提供一个浏览器环境的命令行接口
$ cnpm install --save-dev karma-phantomjs-launcher
参考官网 https://www.npmjs.com/package/karma-phantomjs-launcher ，修改karma.conf.js
运行
$ karma start --browsers PhantomJS_custom
11 11 2017 11:10:29.055:WARN [karma]: No captured browser, open http://localhost:8080/
11 11 2017 11:10:29.071:INFO [karma]: Karma v1.7.1 server started at http://0.0.0.0:8080/
11 11 2017 11:10:29.071:INFO [launcher]: Launching browser PhantomJS_custom with unlimited concurrency
11 11 2017 11:10:29.086:INFO [launcher]: Starting browser PhantomJS
11 11 2017 11:10:29.133:INFO [phantomjs.launcher]: ACTION REQUIRED:
11 11 2017 11:10:29.133:INFO [phantomjs.launcher]:
11 11 2017 11:10:29.133:INFO [phantomjs.launcher]: Launch browser at
11 11 2017 11:10:29.133:INFO [phantomjs.launcher]: http://localhost:9000/webkit/inspector/inspector.html?page=2
11 11 2017 11:10:29.133:INFO [phantomjs.launcher]:
11 11 2017 11:10:29.133:INFO [phantomjs.launcher]: Waiting 15 seconds ...
11 11 2017 11:10:47.356:INFO [PhantomJS 2.1.1 (Windows 8 0.0.0)]: Connected on socket gYJpL9b4Ax1vcSXRAAAA with id 54603354
PhantomJS 2.1.1 (Windows 8 0.0.0): Executed 2 of 2 SUCCESS (0 secs / 0.017 secs)
3.4 代码覆盖率
代码覆盖率常常被拿来作为衡量测试好坏的指标
cnpm install karma karma-coverage --save-dev
参照官网 https://www.npmjs.com/package/karma-coverage 修改karma.conf.js
// coverage settings
// coverage reporter generates the coverage
reporters: ['progress', 'coverage'],
preprocessors: {
// source files, that you wanna generate coverage for
// do not include tests or libraries
// (these files will be instrumented by Istanbul)
'src/**/*.js': ['coverage']
},
// optionally, configure the reporter
coverageReporter: {
type : 'html',
dir : 'coverage/'
},
// end coverage settings done
运行
λ karma start
11 11 2017 15:44:39.502:WARN [karma]: No captured browser, open http://localhost:8080/
11 11 2017 15:44:39.502:INFO [karma]: Karma v1.7.1 server started at http://0.0.0.0:8080
/
11 11 2017 15:44:39.518:INFO [launcher]: Launching browsers PhantomJS, PhantomJS_custom
with unlimited concurrency
11 11 2017 15:44:39.518:INFO [launcher]: Starting browser PhantomJS
11 11 2017 15:44:39.565:INFO [launcher]: Starting browser PhantomJS
11 11 2017 15:44:39.580:INFO [phantomjs.launcher]: ACTION REQUIRED:
11 11 2017 15:44:39.580:INFO [phantomjs.launcher]:
11 11 2017 15:44:39.580:INFO [phantomjs.launcher]: Launch browser at
11 11 2017 15:44:39.580:INFO [phantomjs.launcher]: http://localhost:9000/webkit/inspec
tor/inspector.html?page=2
11 11 2017 15:44:39.580:INFO [phantomjs.launcher]:
11 11 2017 15:44:39.580:INFO [phantomjs.launcher]: Waiting 15 seconds ...
11 11 2017 15:44:42.665:INFO [PhantomJS 2.1.1 (Windows 8 0.0.0)]: Connected on socket tR
S1I1S_vRFKRXcwAAAA with id 93001704
11 11 2017 15:44:57.665:INFO [PhantomJS 2.1.1 (Windows 8 0.0.0)]: Connected on socket dk
GUuJAC80MqA_98AAAB with id 67337991
PhantomJS 2.1.1 (Windows 8 0.0.0): Executed 2 of 2 SUCCESS (0.016 secs / 0.01 secs)
PhantomJS 2.1.1 (Windows 8 0.0.0): Executed 2 of 2 SUCCESS (0 secs / 0.012 secs)
TOTAL: 4 SUCCESS
查看生成的代码覆盖率
$ ls "coveragePhantomJS 2.1.1 (Windows 8 0.0.0)
base.css index.html prettify.css prettify.js sort-arrow-sprite.png sorter.js
4 在测试中注入html，访问DOM元素
4.1 将html写入到js中
源码：https://github.com/shenjiefeng/js-fortest/tree/master/angularjs/ex02-karma-tutorial
4.2 从外部html文件导入
将html写入到js中太麻烦了，可不可以用karma-fixture来实现导入呢
karma start
11 11 2017 16:12:49.337:WARN [karma]: No captured browser, open http://localhost:9876/
11 11 2017 16:12:49.353:INFO [karma]: Karma v1.7.1 server started at http://0.0.0.0:9876/
11 11 2017 16:12:49.353:INFO [launcher]: Launching browsers PhantomJS, PhantomJS_custom with unlimited concurrency
11 11 2017 16:12:49.368:INFO [launcher]: Starting browser PhantomJS
11 11 2017 16:12:49.399:INFO [launcher]: Starting browser PhantomJS
11 11 2017 16:12:49.415:INFO [phantomjs.launcher]: ACTION REQUIRED:
11 11 2017 16:12:49.415:INFO [phantomjs.launcher]:
11 11 2017 16:12:49.415:INFO [phantomjs.launcher]: Launch browser at
11 11 2017 16:12:49.415:INFO [phantomjs.launcher]: http://localhost:9000/webkit/inspector/inspector.html?page=2
11 11 2017 16:12:49.415:INFO [phantomjs.launcher]:
11 11 2017 16:12:49.415:INFO [phantomjs.launcher]: Waiting 15 seconds ...
11 11 2017 16:12:52.545:INFO [PhantomJS 2.1.1 (Windows 8 0.0.0)]: Connected on socket ddCmyvggaUdxkr1rAAAA with id 6133081
11 11 2017 16:13:07.557:INFO [PhantomJS 2.1.1 (Windows 8 0.0.0)]: Connected on socket C670QlbDCLLzPfHYAAAB with id 60711068
LOG: Fixture{base: 'test', id: 'fixture_container', json: [], scriptTypes: Object{application/ecmascript: 1, application/javascript: 1, application/x-ecmascript: 1, application/x-javascript: 1, text/ecmascript: 1, text/javascript: 1, text/javascript1.0: 1, text/javascript1.1: 1, text/javascript1.2: 1, text/javascript1.3: 1, text/javascript1.4: 1, text/javascript1.5: 1, text/jscript: 1, text/livescript: 1, text/x-ecmascript: 1, text/x-javascript: 1}, el: <div id="fixture_container"></div>}
PhantomJS 2.1.1 (Windows 8 0.0.0) Calculator should return 3 for 1 + 2 FAILED
ReferenceError: Cannot find fixture 'test/hello.html' in node_modules/_karma-fixture@0.2.6@karma-fixture/lib/fixture.js (line 141)
_throwNoFixture@node_modules/_karma-fixture@0.2.6@karma-fixture/lib/fixture.js:141:77
load@node_modules/_karma-fixture@0.2.6@karma-fixture/lib/fixture.js:78:33
test/calculator.test.js:49:24
executeFiltered@node_modules/_karma-jasmine@0.2.3@karma-jasmine/lib/boot.js:126:18
node_modules/_karma-jasmine@0.2.3@karma-jasmine/lib/adapter.js:171:31
loaded@http://localhost:9876/context.js:162:17
global code@http://localhost:9876/context.html:48:28
TypeError: null is not an object (evaluating 'document.getElementById('x').value = 1') in test/calculator.test.js (line 60)
test/calculator.test.js:60:33
executeFiltered@node_modules/_karma-jasmine@0.2.3@karma-jasmine/lib/boot.js:126:18
node_modules/_karma-jasmine@0.2.3@karma-jasmine/lib/adapter.js:171:31
loaded@http://localhost:9876/context.js:162:17
global code@http://localhost:9876/context.html:48:28
对应的代码覆盖率：
可以看出，9句中4句未覆盖。
如何解决ReferenceError: Cannot find fixture 'test/hello.html'问题呢？
几经尝试，还是同样的问题，忧桑啊。