在Mocha测试中使用for循环 [英] Using a for loop in a Mocha Test
问题描述
我是mocha的新手，我想尝试使用for循环来创建测试用例。我想测试一个我所做的功能，它输入标准的12小时时间，然后输出到24小时的军事时间。这就是它的样子。
I'm new to mocha, and I wanted to try using a for loop to create test cases. I want to test a function that I've made that takes an input of standard 12 hour time, and outputs it into 24 hour military time. This is what it looks like.
exports.main = function(time) {
var hr = parseInt(time.substr(0,2));
var period = time.substr(8,10);
if (period == 'AM' && hr == 12) {
hr = '0';
}
if (period == 'PM' && hr < 12) {
hr += 12;
}
hr.toString();
if (hr < 10) {
hr = '0' + hr;
}
return time = time.replace(/^\d{2}/g, hr).substr(0,8);
}
要在mocha中测试我的函数，我有两个数组，一个数组保持标准时间，另一个数组保持相应的预期输出。我想迭代它们并为每次迭代生成一个测试用例并测试我的函数。
To test my function in mocha, I have two arrays, one array holds the standard times and the other holds the corresponding expected output. I want to iterate through them and produce a test case for each iteration and test my function.
test_array = ["12:00:00AM", "01:00:00AM", "02:00:00AM", "03:00:00AM", "04:00:00AM",
"05:00:00AM", "06:00:00AM", "07:00:00AM", "08:00:00AM", "09:00:00AM",
"10:00:00AM", "11:00:00AM", "12:00:00PM", "01:00:00PM", "02:00:00PM",
"03:00:00PM", "04:00:00PM", "05:00:00PM", "06:00:00PM", "07:00:00PM",
"08:00:00PM", "09:00:00PM", "10:00:00PM", "11:00:00PM"];
against = ["00:00:00", "01:00:00", "02:00:00", "03:00:00", "04:00:00",
"05:00:00", "06:00:00", "07:00:00", "08:00:00", "09:00:00", "10:00:00",
"11:00:00", "12:00:00", "13:00:00", "14:00:00", "15:00:00", "16:00:00",
"17:00:00", "18:00:00", "19:00:00", "20:00:00", "21:00:00", "22:00:00",
"23:00:00"]
这是我的测试脚本是什么样的：
This is what my test script looks like:
var converter = require('../modules/time.js');
describe('Time Converter', function() {
describe('main()', function() {
for(i = 0; i < 24; i++) {
it(test_array[i] + ' should convert to ' + against[i], function() {
var test = converter.main(test_array[i]);
assert.equal(test, against[i]);
});
}
});
});
以下是测试结果：
0 passing (23ms)
24 failing
1) Time Converter main() 12:00:00AM should convert to 00:00:00:
TypeError: Cannot read property 'substr' of undefined
at Object.exports.main (app/modules/time.js:43:27)
at Context.<anonymous> (app/test/test.js:35:26)
2) - 24) has the same result:
24) Time Converter main() 11:00:00PM should convert to 23:00:00:
TypeError: Cannot read property 'substr' of undefined
at Object.exports.main (app/modules/time.js:43:27)
at Context.<anonymous> (app/test/test.js:35:26)
但是当我改变了for循环到
for(i = 0; i < 23; i++)
所有测试都通过，但自然不会测试最后一个测试用例。
All the tests pass except, naturally it doesn't test the last test case.
Time Converter
main()
✓ 12:00:00AM should convert to 00:00:00
✓ 01:00:00AM should convert to 01:00:00
✓ 02:00:00AM should convert to 02:00:00
✓ 03:00:00AM should convert to 03:00:00
✓ 04:00:00AM should convert to 04:00:00
✓ 05:00:00AM should convert to 05:00:00
✓ 06:00:00AM should convert to 06:00:00
✓ 07:00:00AM should convert to 07:00:00
✓ 08:00:00AM should convert to 08:00:00
✓ 09:00:00AM should convert to 09:00:00
✓ 10:00:00AM should convert to 10:00:00
✓ 11:00:00AM should convert to 11:00:00
✓ 12:00:00PM should convert to 12:00:00
✓ 01:00:00PM should convert to 13:00:00
✓ 02:00:00PM should convert to 14:00:00
✓ 03:00:00PM should convert to 15:00:00
✓ 04:00:00PM should convert to 16:00:00
✓ 05:00:00PM should convert to 17:00:00
✓ 06:00:00PM should convert to 18:00:00
✓ 07:00:00PM should convert to 19:00:00
✓ 08:00:00PM should convert to 20:00:00
✓ 09:00:00PM should convert to 21:00:00
✓ 10:00:00PM should convert to 22:00:00
23 passing (14ms)
然而，当我自己测试最后一个测试用例时，它会通过。
However when I test the last test case by itself, it passes.
✓ 11:00:00PMshould convert to 23:00:00
所以，我很困惑为什么所有如果for循环遍历整个数组，则测试不起作用，但如果我迭代直到最后一个索引，则测试工作。有人可以为我清除这个吗？
推荐答案
您的代码可能是同步的，但是mocha将其称为异步。意思是：你的描述被解析同步，mocha存储这些信息并在它自己的上下文中运行每个测试。这是异步的。为了使这个工作，你必须创建一个带函数的闭包：
Your code may be sync, but mocha calls it it async. Means: your it descriptions are parsed sync, mocha stores this information and runs every test in it's own context. This is async. To make this work, you have to create a closure with a function:
var converter = require('../modules/time.js');
// outside the loop:
function itShouldTestArray(i) {
// i is now within the function scope and won't change anymore
it(test_array[i] + ' should convert to ' + against[i], function() {
var test = converter.main(test_array[i]);
assert.equal(test, against[i]);
}
describe('Time Converter', function() {
describe('main()', function() {
for(i = 0; i < 24; i++) {
itShouldTestArray(i);
});
}
});
});
这篇关于在Mocha测试中使用for循环的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
