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我有一个用 ES6 之前的 JS 代码编写的纯 JS 文件，我想使用 karma/jasmine 测试套件进行测试。该文件很大，但我只想让一个超级简单的示例正常工作。

// pluginV3.js
// This is the file I am trying to test. It is written in pre ES6 JS and has no exports
var myvar = null;

我找到了一个名为rewire的库，我认为它可以让我测试像这样的普通 JS 文件，但我无法让它与我的 karma/jasmine 堆栈一起工作。到目前为止，我已经尝试过：

// var rewire = require("rewire"); // Can't use require. Test code is also pre ES6
beforeEach(module('rewire')); // I have been trying to instance "rewire" here using the exported module in rewire's index.js  

describe('V3 Helper.js', function() {
    describe('$pluginV3.myvar', function () {
        fit('Tests a certain variable in pluginV3 is set to an expected initial value', function () {
            var pluginV3 = rewire("../../../../public/static/js2/pluginV3.js");
            expect(pluginV3.myvar).toEqual(null); // expect this scope var to be something
        });
    });
});

但我得到这个错误：

LOG: '----------------------------------------------------'
Chrome 96.0.4664.55 (Mac OS 10.15.7): Executed 0 of 30 SUCCESS (0 secs / 0 secs)
LOG: 'What is rewire?'
Chrome 96.0.4664.55 (Mac OS 10.15.7): Executed 0 of 30 SUCCESS (0 secs / 0 secs)
LOG: function rewire(filename) { ... }
Chrome 96.0.4664.55 (Mac OS 10.15.7): Executed 0 of 30 SUCCESS (0 secs / 0 secs)
Chrome 96.0.4664.55 (Mac OS 10.15.7) CN Plugin Client V3 Helper $scope.transferData Tests a certain variable in Plugin Client V3 is set to an expected initial value FAILED
    TypeError: rewireModule is not a function
        at rewire (node_modules/rewire/lib/index.js:11:12)
        at UserContext.<anonymous> (tests/helpers/cn-plugin-client-v3-test.js:25:28)
        at <Jasmine>
Chrome 96.0.4664.55 (Mac OS 10.15.7): Executed 1 of 30 (1 FAILED) (0 secs / 0.002 secs)
Chrome 96.0.4664.55 (Mac OS 10.15.7) CN Plugin Client V3 Helper $scope.transferData Tests a certain variable in Plugin Client V3 is set to an expected initial value FAILED
    TypeError: rewireModule is not a function
        at rewire (node_modules/rewire/lib/index.js:11:12)
        at UserContext.<anonymous> (tests/helpers/cn-plugin-client-v3-test.js:25:28)
        at <Jasmine>

这让我觉得它beforeEach(module('rewire'));正在工作，但由于某种原因它无法运行 rewireModule（也许是因为它是 ES6+）？这是 rewire 的 index.js：

var rewireModule = require("./rewire.js");

/**
 * Adds a special setter and getter to the module located at filename. After the module has been rewired, you can
 * call myModule.__set__(name, value) and myModule.__get__(name) to manipulate private variables.
 *
 * @param {!String} filename Path to the module that shall be rewired. Use it exactly like require().
 * @return {*} the rewired module
 */
function rewire(filename) {
    return rewireModule(module.parent, filename);
}

module.exports = rewire;

delete require.cache[__filename];   // deleting self from module cache so the parent module is always up to date

这是我在我的 karmaconfig 文件中导入的内容以及我要测试的文件：

// karma.conf.js
files: [
            './node_modules/rewire/lib/index.js',
            '../../public/static/js2/cn-plugin-client-v3.js',
    ]

难道我做错了什么？或者我只是无法在 ES6 之前的限制下使用 rewire。有没有人用 karma/jasmine 测试过没有导出的 pre ES6 JS 文件？有不同的解决方案吗？

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1 回答 1

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事实证明，重新布线是不必要的。将文件添加到 karma 配置后，通常可以通过将其作为模块调用来在测试中实例化它：

beforeEach(module('pluginV3'));

这种方法的唯一缺点是您需要满足每个依赖项。如果其中有一个变量pluginV3.js来自pluginV2.js或其他东西，您需要在依赖它的文件之前将其添加到业力文件导入中。

我没有测试这么多，但我想这个解决方案对于具有不切实际的长依赖链的文件仍然不够，我不知道你将如何处理具有循环依赖的文件。

于 2021-12-08T14:48:18.693 回答