Unable to import a React Component in my Mocha tes

Question

I"m trying to do a simple Mocha test, which works, but once i start trying to add my own components for testing, it is unable to resolve the module.

package.json:

{
  "name": "My Project",
  "version": "0.1.0",
  "scripts": {
    "test": "mocha \"./src/**/*.spec.js\""
  },
  "dependencies": {
    "react": "^0.14.7",
    "react-dom": "^0.14.7",
    "webpack": "^1.12.12"
  },
  "devDependencies": {
    "bower": "^1.4.1",
    "expect": "^1.14.0",
    "expect-jsx": "^2.3.0",
    "jsx-loader": "^0.13.2",
    "mocha": "^2.4.5",
    "react-addons-test-utils": "^0.14.7"
  }
}

src/dashboard/TestComponent.jsx:

var React = require('react');
var TestComponent = React.createClass({

    render: function() {
        return (
            <div />
        );
    }
});

module.exports = TestComponent;

src/dashboard/test.spec.js:

var React = require("react");
var ReactTestUtils = require('react-addons-test-utils');
var expect = require("expect");
var expectJSX = require("expect-jsx");  
expect.extend(expectJSX);

var TestComponent = require('./TestComponent');

describe('Test', function() {
    it('should work', function() {
        expect(true).toEqual(true)
    });
});

If i remove the line var TestComponent = require('./TestComponent.jsx');, my spec passes. But once i try to require my component, it gives me this error:

$ npm test

>My Project@0.1.0 test C:\workspace\root
>mocha "./src/**/*.spec.js"

module.js:338
    throw err;
          ^ Error: Cannot find module './TestComponent'
    at Function.Module._resolveFilename (module.js:336:15)
    at Function.Module._load (module.js:278:25)
    at Module.require (module.js:365:17)
    at require (module.js:384:17)
    at Object.<anonymous> (C:\workspace\root\src\dashboard\test.spec.js:7:22)
    at Module._compile (module.js:460:26)
    at Object.Module._extensions..js (module.js:478:10)
    at Module.load (module.js:355:32)
    at Function.Module._load (module.js:310:12)
    at Module.require (module.js:365:17)
    at require (module.js:384:17)
    at C:\workspace\root\node_modules\mocha\lib\mocha.js:219:27
    at Array.forEach (native)
    at Mocha.loadFiles (C:\workspace\root\node_modules\mocha\lib\mocha.js:216:14)
    at Mocha.run (C:\workspace\root\node_modules\mocha\lib\mocha.js:468:10)
    at Object.<anonymous> (C:\workspace\root\node_modules\mocha\bin\_mocha:403:18)
    at Module._compile (module.js:460:26)
    at Object.Module._extensions..js (module.js:478:10)
    at Module.load (module.js:355:32)
    at Function.Module._load (module.js:310:12)
    at Function.Module.runMain (module.js:501:10)
    at startup (node.js:129:16)
    at node.js:814:3 npm ERR! Test failed.  See above for more details.

Answer 1

Mocha probably can't read your TestComponent because it contains syntax unfamiliar to it (the JSX). You'll need to specify a compiler for mocha as well as babel presets (assuming you're using Babel).

Assuming you already have babel-core and babel-preset-react installed for your project, make these changes in your package.json:

"scripts": {
  "test": "mocha --compilers js:babel-register \"./src/**/*.spec.js\""
},
"babel": {
  "presets": ["react"]
}

Answer 2

You should add the .jsx extension to your require call, as by default it won't recognize .jsx files as modules.

Rick is also right about the compiler but in this case the error is due to the synthax of require. Then if you fix the require you will see an error of unexpected token, which is the lack of compiler.

You should therefore correct both points.