Default jest config file jest.config.js is ignored.

[Andrey Kutejko]

[Simon de Lang]

Thanks for opening this issue! Could you please post your stryker.conf.js?

[Andrey Kutejko]

This works

module.exports = function(config) {
  config.set({
    files: [
      { pattern: "assets/**/*.js", mutated: true, included: false },
    ],
    testRunner: "jest",
    mutator: "javascript",
    transpilers: ["babel"],
    reporter: ["html", "baseline", "clear-text", "progress"],
    coverageAnalysis: "off",
    babelrcFile: ".babelrc",
    jest: {
        project: 'default',
        config: require(__dirname + '/jest.config.js')
    },
    "logLevel": "all",
  });
};

but this doesn't

module.exports = function(config) {
  config.set({
    files: [
      { pattern: "assets/**/*.js", mutated: true, included: false },
    ],
    testRunner: "jest",
    mutator: "javascript",
    transpilers: ["babel"],
    reporter: ["html", "baseline", "clear-text", "progress"],
    coverageAnalysis: "off",
    babelrcFile: ".babelrc",
//    jest: {
//        project: 'default',
//        config: require(__dirname + '/jest.config.js')
//    },
    "logLevel": "all",
  });
};

[Simon de Lang]

That the expected behavior. If you don't specify anything related to your jest config, the plugin will look for a jest config in your package.json. If you want to require a file, you will have to do that with the config you provided here.

How do you suggest we make this clearer in the README for this package? Or perhaps combined with more extensive logging?

[Andrey Kutejko]

But jest.config.js is recognized by Jest itself.

[Simon de Lang]

Good point! If Jest can find it by default, I would expect Stryker to find it as well by default. What are your thoughts @Archcry ?

[Sander Koenders]

According to the Configuring Jest page you can indeed choose to specify the jest configuration in the jest.config.js. It seems like jest is trying to load the package.json first and then tries to fall back on the jest.config.js. I think we can replicate this functionality in Stryker by trying to load the package.json config first and if that does not succeed load the jest.config.js.

The page does not explicitly state which config is tried first though, thoughts on that?

[Nico Jansen]

@Archcry, try it out with a little expiriment? :)

[Simon de Lang]

It first looks for jest.config.js and then it will look in your package.json for a jest property.
I tested this with:

// jest.config.js
module.exports = {
    verbose: true,
};

And package.json:

"scripts": {
    "test": "jest"
  },
"jest": {
    "collectCoverage": true,
    "collectCoverageFrom": [
      "sum.js"
    ],
    "coverageDirectory": "./coverage"
  }

The result was a Jest run without coverage. If I remove the jest.config.js file I do get a coverage result from Jest.