Node Assert

1. 关于Node Assert

顾名思义应该就是跑测试用例里的断言吧，里面有各种接口判断

assert() 和true比较

assert.deepEqual(v1,v2，[message])把v1,v2进行比较，针对对象的比较

const obj1 = {

  a : {

    b : 1

  }

};

const obj2 = {

  a : {

    b : 2

  }

};

const obj3 = {

  a : {

    b : 1

  }

}

const obj4 = Object.create(obj1);

assert.deepEqual(obj1, obj1);

  // OK, object is equal to itself

assert.deepEqual(obj1, obj2);

  // AssertionError: { a: { b: 1 } } deepEqual { a: { b: 2 } }

  // values of b are different

assert.deepEqual(obj1, obj3);

  // OK, objects are equal

assert.deepEqual(obj1, obj4);

  // AssertionError: { a: { b: 1 } } deepEqual {}

  // Prototypes are ignored

assert.deepStrcitEqual(v1,v2,[message])比较v1,v2, 针对对象，会深层遍历对象，执行===规则比较

const assert = require('assert');

assert.deepEqual({a:1}, {a:'1'});

  // OK, because 1 == '1'

assert.deepStrictEqual({a:1}, {a:'1'});

  // AssertionError: { a: 1 } deepStrictEqual { a: '1' }

  // because 1 !== '1' using strict equality

assert.doesNotThrow(block,[message])直接执行block内容，如果block块抛出的异常类型和指定的异常类型相同，则抛出AssertionError, 反之则抛出指定的异常

assert.doesNotThrow(

  () => {

    throw new TypeError('Wrong value');

  },

  SyntaxError

);

assert.doesNotThrow(

  () => {

    throw new TypeError('Wrong value');

  },

  TypeError

);

assert.doesNotThrow(

  () => {

    throw new TypeError('Wrong value');

  },

  TypeError,

  'Whoops'

);

// Throws: AssertionError: Got unwanted exception (TypeError). Whoops

assert.equal(v1,v2,message)

assert.equal(1, 1);

  // OK, 1 == 1

assert.equal(1, '1');

  // OK, 1 == '1'

assert.equal(1, 2);

  // AssertionError: 1 == 2

assert.equal({a: {b: 1}}, {a: {b: 1}});

  //AssertionError: { a: { b: 1 } } == { a: { b: 1 } }

assert.fail(actual, expected, message, operator)总是抛出AssertError异常无论是否满足条件，将actual和expected用operator比较，如果message为false则AssertError信息为actual operator expected, 如果message为true则显示message

assert.fail(1, 2, undefined, '>');

  // AssertionError: 1 > 2

assert.fail(1, 2, 'whoops', '>');

  // AssertionError: whoops

Note:运行assert.fail(1, 2, undefined, '<'); 输出：AssertionError: 1<2

assert.ifError(value) 当value为true时输出value

const assert = require('assert');

assert.ifError(0); // OK

assert.ifError(1); // Throws 1

assert.ifError('error') // Throws 'error'

assert.ifError(new Error()); // Throws Error

assert.notDeepEqual(actual, expected[, message]) 和assert.deepEqual(actual, expected[, message]) 相反

assert.notDeepStrictEqual(actual, expected[, message])和assert.deepStrictEqual(actual, expected[, message])相反

assert.ok(value[, message])测试value是否为true, 否则抛出AssertError异常

const assert = require('assert');

assert.ok(true);  // OK

assert.ok(1);    // OK

assert.ok(false);

  // throws "AssertionError: false == true"

assert.ok(0);

  // throws "AssertionError: 0 == true"

assert.ok(false, 'it\'s false');

  // throws "AssertionError: it's false"

assert.strictEqual(actual, expected[, message])比较规则和===相同

assert.strictEqual(1, 2);

  // AssertionError: 1 === 2

assert.strictEqual(1, 1);

  // OK

assert.strictEqual(1, '1');

  // AssertionError: 1 === '1'

assert.throws(block[, error][, message])期望block抛出异常，error不可以是string类型