jasmine
简介
jasmine 是一个测试驱动开发(TDD)测试框架， 一个js测试框架，它不依赖于浏览器、dom或其他js框架
jasmine有十分简洁的语法
使用
从 这里 下载 stantd-alone安装包，并解压，双击打开里面的 specRunner.html， 即可看到测试示例，我们只要将自己的js源文件和测试文件分别放到 src 和 spec 文件夹中。
specRunner.html 到底是长什么样子的呢？ f12 我们发现 先后加载了 jasmine.css， jasmine.js ，jasmine-html.js， boot.jsjasmine框架相关文件和 我们的 js源文件 jasmine测试文件
语法
分组 describe()
describe的作用是群组相关的测试, describe是可以嵌套的 从外到内 walkdown describe层级的 beforeEach, 由内到外walkup describe层级的 afterEach
describe('a suite', function(){ //这是一个测试分组
it('with an expactation',function(){
expect(true).toBe(true);
});
});
测试it()
describe 和 it 都是函数，所以它们可以包含任何js代码， 在 describe 中声明的变量和方法，能在 it中被访问。
it 代表的是具体的测试，当其中所有的断言都为true时，则该测试通过； 否则测试失败
describe('a suit is just a function', function(){
var a = 10;
it('and here is a test', function(){
var a = true;
expect(a).toBe(true);
});
});
期望expect()
desribe('the "toBe" matcher compares with "===" ', function(){
it('positive expect', function(){
expect(true).toBe(true);
});
it('negative expect', function(){
expect(false).not.toBe(true);
});
});
匹配 to*()
每个匹配方法在期望值和实际值之间执行逻辑比较，它负责告诉jasmine断言的真假，从而决定测试的成功或失败。
肯定断言 expect(true).toBe(true);
否定断言 expect(false).not.toBe(true);
jasmine有很丰富的匹配方法，而且可以自定义匹配方法。 内置的匹配方法有：
toBe()
toEqual()
toMatch()
toBeUndefined()
toBeNull()
toBeTruthy()
toContain()
toBeLessThan()
toBeCloseTo()
toThrowError()
describe("included matchers", function(){
it('"toBe" matcher compares width === ', function(){
var a = 12;
var b = a;
expect(a).toBe(b);
expect(a).not.toBe(null);
}); describe('"toEqual" matcher', function(){
it('work for simple literals and variable', function(){
var a = 12;
expect(a).toEqual(12);
}); it('should work for objects', function(){
var foo = {
a: 12,
b: 23
};
var bar = {
a: 12,
b: 23
}; expect(foo).toEqual(bar); //true?
});
}); it('"toMatch" matcher is for regular expression', function(){
var message = "foo bar baz";
expect(message).toMatch(/bar/);
expect(message).toMatch("bar");
expect(message).not.toMatch(/quue/);
}); it('"toBeUndefined" matcher compares against "undefined"', function(){
var a = {
foo: "foo"
}; expect(a.foo).not.toBeUndefined();
expect(a.bar).toBeUndefined();
}); it(' "toBeNull" matcher compares against "null"', function(){
var a = null;
var foo = 'foo'; expect(null).toBeNull();
expect(a).toBeNull();
expect(foo).not.toBeNull();
}); it('"toBeTruthy" matcher is for boolean casting testing' , function(){
var a, foo = 'foo';
expect(foo).toBeTruthy();
expect(a).not.toBeTruthy();
}); it('"toContain" matcher is for finding an item in an array', function(){
var a = ['foo', 'bar', 'baz'];
expect(a).toContain('bar');
expect(a).not.toContain('quu');
}); it('"toBeLessThan" matcher is for math comparisons', function(){
var n = 2.23, e = 1.33;
expect(e).toBeLessThan(n);
expect(n).not.toBeLessThan(e);
}); it('"toBeCloseTo" matcher is for precision match comparison', function(){
var n = 1.99, e = 2.35;
expect(e).not.toBeCloseTo(n, 2);
expect(e).toBeCloseTo(n, 0);
}); it('"toThrowError" matcher is for testing a specific thrown exception', function(){
var foo = function(){
throw new TypeError('foo bar baz');
};
expect(foo).toThrowError('foo bar baz');
expect(foo).toThrowError(/bar/);
expect(foo).toThrowError(TypeError);
expect(foo).toThrowError(TypeError, 'foo bar baz');
});
});
设置和清理 beforeEach(), afterEach()
beforeEach() 在它所属的 describe 块中的每条测试执行前，先执行的js代码， 作用就是设置和初始化一些东西。afterEach() 和 beforeEach 相反，在 describe 块的每条测试执行后执行， 做一些清理的工作。
describe('tests with "setup" and "tear-down"', function(){
var foo;
beforeEach(function(){
foo = 0;
foo += 1; //每次测试前都初始化 foo == 1
});
afterEach(function(){
foo = 0; //每次测试完都重置 foo = 0;
});
it('it is just a function , so can contain any code', function(){
expect(foo).toEqual(1);
});
it('can have more than one expectation', function(){
expect(foo).toEqual(1);
expect(true).toEqual(true);
});
});
this对象
另一种在 beforeEach afterEach it 之间共享变量的方法： this对象, 每次执行完1条测试之后，this 都会被重置为空对象
describe('a suite', function(){
beforeEach(function(){
this.foo = 0;
});
it('can use "this" to share initial data', function(){
expect(this.foo).toEqual(0);
this.bar = "test pollution?";
});
it('prevents test pollution by having an empty "this" created for next test', function(){
expect(this.foo).toEqual(0);
expect(this.bar).toBe(undefined);
});
});
describe嵌套 beforeEach串行
describe('a suite', function(){
var foo;
beforeEach(function(){
foo = 0;
foo += 1;
});
afterEach(function(){
foo = 0;
});
it('a spec', function(){
expect(foo).toEqual(1);
});
it('a spec too', function(){
expect(foo).toEqual(1);
expect(true).toEqual(true);
});
describe('nested inside describe', function(){
var bar;
beforeEach(function(){
bar = 1;
});
// exec outer's describe beforeEach > this describe's beforeEach
it('可以访问外部describe的beforeEach的变量', function(){
expect(foo).toEqual(bar);
});
});
});
禁用describe或it
xdescribe(), xit() 和 pending()
xdescribe('a suite',function(){
//will not execute
});
describe('a suite too', function(){
xit('this test be canceled', function(){
expect(true).toBe(false);
});
it('can be desclared with "it" but without a function');
if('can be declared by calling "pending()" in spec body', function(){
expect(true).toBe(false);
pending(); //禁用该测试
});
});
函数调用监听 spy
spyOn() , toHaveBeenCalled() , toHaveBeenCalledWith()
describe('a spy', function(){
var foo, bar = null;
beforeEach(function(){
foo = {
setBar = function(value){
bar = value;
};
};
spyOn(foo, 'setBar');
foo.setBar(123);
foo.setBar(456, 'another param');
});
it('tracks that the spy was called', function(){
expect(foo.setBar).toHaveBeenCalled();
});
it('tracks all the arguments of its calls', function(){
expect(foo.setBar).toHaveBeenCalledWith(123);
expect(foo.setBar).toHaveBeenCalledWith(456, 'another param');
});
it('stops all execution on a function', function(){
expect(bar).toBeNull(); //setBar函数的执行 被spy监听器暂停了。
});
});
describe('a spy, when configured to call through', function(){
var foo , bar, fetchedBar;
beforeEach(function(){
foo = {
setBar: function(value){
bar = value;
},
getBar: function(){
return bar;
}
};
spyOn(foo, 'getBar').and.callThrough();
foo.setBar(123);
fetchedBar = foo.getBar();
});
it('tracks that the spy was called', function(){
expect(foo.getBar).toHaveBeenCalled();
});
it('should not effect other function', function(){
expect(bar).toEqual(123);
});
it('when called returns the requested value' , function(){
expect(fetchedBar).toEqual(123);
})
});