jasmine官方api参考

jasmine

简介

jasmine 是一个行为驱动开发(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有十分简介的语法

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的作用的群组相关的测试, 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);
	})
});