Question

我正在尝试编写单元测试。如果函数得到负数，则会抛出新错误。

   Obj = function () { 
}; 
Obj.prototype.Count = function (number) { 
    if (number < 0) { 
        throw new Error("There is no function for negative numbers"); 
    } else...

我的unit-tet功能：

function test(then,expected) {
        results.total++;
        var m1=new Obj();
        if (m1.Count(then)!=expected){
          results.bad++;
            alert(m1.Count(then)+" not equal "+expected);
        }
    }
    var results = {
        total: 0,
        bad: 0
    };

然后我正在尝试运行测试

test(5,120) 
test(-5, "There is no function for negative numbers");

第一个正常工作，但我不知道对于负数会写什么'预期'。该示例不起作用。你能告诉我吗？

谢谢！

Answer 1

If you are going to test errors, you'll need to use a try ... catch.

var Obj = function() {};
Obj.prototype.count = function(num) {
    if (num < 0) throw new Error("Invalid Number");
    else return 0;
}

function test(value, expected) {
    results.total++;
    var obj = new Obj();
    try {
        obj.count(value);
    }
    catch (err) {
        if (err.message != expected) results.bad++;
    }
}

And then:

test(-5, 'Invalid Number'); // doesn't add one to results.bad

如何测试抛出新的错误JavaScript

1 个答案: