javascript-使用Karma&Mocha.js对多个用例进行单元测试

我对测试还很陌生,所以这个问题是关于最佳实践以及该测试应该如何编写的.我正在将Karma与Mocha和Chai一起测试Angular.js应用.

我目前正在测试一个函数,该函数计算以特定顺序排列字母组合的方式的数量.它遵循一种模式来从辅音组或元音组中提取字母.

这些是我目前的测试：

describe("should count the number of combinations correctly", function() {  describe("with 2-item arrays", function() {    beforeEach(function(){      scope.vowels = ['a', 'e'];      scope.consonants = ['b', 'c'];    })    it("with 2 letters in pattern", function() {      scope.pattern = 'CV';      expect(scope.combinationCounter()).to.equal(4);    });    it("with 3 letters in pattern", function() {      scope.pattern = 'CVC';      expect(scope.combinationCounter()).to.equal(8);    });    it("with 4 letters in pattern", function() {      scope.pattern = 'CVCV';      expect(scope.combinationCounter()).to.equal(16);    });  });  describe("with 3-item arrays", function() {    beforeEach(function(){      scope.vowels = ['a', 'e', 'i'];      scope.consonants = ['b', 'c', 'd'];    })    it("with 2 letters in pattern", function() {      scope.pattern = 'CV';      expect(scope.combinationCounter()).to.equal(9);    });    it("with 3 letters in pattern", function() {      scope.pattern = 'CVC';      expect(scope.combinationCounter()).to.equal(27);    });    it("with 4 letters in pattern", function() {      scope.pattern = 'CVCV';      expect(scope.combinationCounter()).to.equal(81);    });          });});

这些测试有效,并且它们为我提供了有用的错误消息,但是我不禁感到自己在做一些不必要的重复,因为我实际上是在使用不同的值执行相同的测试.

有没有一种方法可以编写这些测试来维护错误消息的结构,但是不需要我写出来

it("with x letters in pattern", function() {  scope.pattern = 'whatever';  expect(scope.combinationCounter()).to.equal(y);});  

每一次？

我想在没有巨大测试文件的情况下测试大量案例,但请保持错误消息的可读性.

编辑：@Stas回答的问题

@Stas给了我正确的答案,那就是使用带有对象的循环来容纳不同的测试用例.但是,由于他的答案是用lodash编写的(我没有使用过),因此我在下面包括了最终的循环代码以供参考.

我在此处循环播放的场景对象与@Stas示例中的对象相同.

for (var x in scenarios) {  var vowels     = scenarios[x].arrays.vowels;  var consonants = scenarios[x].arrays.consonants;  var v = vowels;  var c = consonants;  describeStuff();}function describeStuff(){   describe("with "   x, function(){    setLetters(v,c);  });}function setLetters(vowels, consonants){  describe("(" vowels   ' & '   consonants   "),", function(){    beforeEach(function(){      scope.vowels = vowels;      scope.consonants = consonants;    });    innerLoop();  });}function innerLoop(){  for (var y in scenarios[x].combinations) {    var combinations = scenarios[x].combinations;    var pat = scenarios[x].combinations[y].pattern;    var res = scenarios[x].combinations[y].result;    setResults(pat, res);  }}function setResults(p, r){  var pattern = p;  var result = r;  it("with "   p.length   " letters in pattern ("   p   ")", function(){    scope.pattern = pattern;    expect(scope.combinationCounter()).to.equal(result);  });}

我必须使用相互调用的四个函数链来编写循环,因为在for in循环中使用Mocha的回调语法只会导致将最终测试用例保存到函数变量中.在循环之外定义函数,然后在内部调用它们可以解决此问题.

解决方法:

您可以创建方案对象并为每个循环包装执行(在此示例中,我使用lodash)：

describe("should count the number of combinations correctly", function () {    var scenarios = {        "2-item arrays": {            arrays: {                vowels: ['a', 'e'],                consonants: ['b', 'c']            },            combinations: [                {pattern: "CV", result: 4},                {pattern: "CVC", result: 8},                {pattern: "CVCV", result: 16}            ]        },        "3-item arrays": {            arrays: {                vowels: ['a', 'e', 'i'],                consonants: ['b', 'c', 'd']            },            combinations: [                {pattern: "CV", result: 9},                {pattern: "CVC", result: 27},                {pattern: "CVCV", result: 81}            ]        }    };    _.forEach(scenarios, function (scenario, key) {        describe("with "   scenario.key, function () {            beforeEach(function () {                scope.vowels = scenario.arrays.vowels;                scope.consonants = scenario.arrays.consonants;            });            _.forEach(scenario.combinations, function(combination) {                it("with "   combination.pattern.length   " letters in pattern", function() {                    scope.pattern = combination.pattern;                    expect(scope.combinationCounter()).to.equal(combination.result);                });            })        });    });});

这样,您可以添加更多方案,而无需为每个组合重复describe()/ beforeEach()/ it(),它将产生相同的消息.

来源：https://www.icode9.com/content-1-568601.html