No way to use custom mocha ui

[stalniy]

Currently it's impossible to use custom mocha ui.
What I want is extra config option which allow to specify which files I want to load before bootstraping mocha (before adapter.js)

var initMocha = function (files, mochaConfig) {
  var mochaPath = path.dirname(require.resolve('mocha'))
  files.unshift(createPattern(__dirname + '/adapter.js'))
  // HERE: I want to iterate over config.mochaFiles and add them right after mocha.js
  files.unshift(createPattern(mochaPath + '/mocha.js'))

  if (mochaConfig && mochaConfig.reporter) {
    files.unshift(createPattern(mochaPath + '/mocha.css'))
  }
}

[claydiffrient]

It seems like in my testing the mocha.opts file isn't respected by karma-mocha.

Putting --require ./test/spec_helper.js inside mocha.opts does nothing.

[stalniy]

Actually the main cause of this exception is that adapter.js is included before custom ui. So, the simplest solution is to check if adapter is already inside files then don't add it otherwise - default logic. Then devs can do this

files: [
  'path/to/my-ui.js',
  require.resolve('karma-mocha/lib/adapter'),
  'path/to/specs/*'
],
client: {
  mocha: {
    ui: 'my-ui'
  }
}

cc: @vojtajina @maksimr @zzo @dignifiedquire

[maksimr]

@stalniy you can create inline adapter for custom mocha reporter and load file before karma-mocha files

[stalniy]

@maksimr this is browser's environment. I need to load files not before mocha.js but right after it (i.e. before adapter.js but not before mocha.js as first one initialize mocha instance). You can try to do this. I wanted to load https://github.com/stalniy/bdd-lazy-var right after mocha. If I do it before I will receive error (Mocha is undefined) as it adds new interface to Mocha.interfaces.

[dtothefp]

Think this is related but it would be nice to have a require option similar to gulp-mocha where we could hook into the --require functionality.

ex.

client: {
  mocha: {
    ui: 'my-ui',
    require: [ path.join(__dirname, 'some-script.js') ]
  }
}

Specifically this would be useful for me to do something like https://labnotes.org/yield-to-the-test-using-mocha-with-es6-generators/ where you could hook into something like mocha.Runnable.prototype.run before instantiation

[christian-schulze]

@stalniy I've had some success getting your https://github.com/stalniy/bdd-lazy-var mocha ui to work by making the following changes to lib/index.js#initMocha:

var initMocha = function (files, mochaConfig) {
  var mochaPath = path.dirname(require.resolve('mocha'))
  var bddLazyVarPath = path.dirname(require.resolve('bdd-lazy-var'))
  files.unshift(createPattern(path.join(__dirname, 'adapter.js')))
  files.unshift(createPattern(path.join(bddLazyVarPath, 'bdd_lazy_var_global.js')))
  files.unshift(createPattern(path.join(mochaPath, 'mocha.js')))

  if (mochaConfig && mochaConfig.reporter) {
    files.unshift(createPattern(path.join(mochaPath, 'mocha.css')))
  }
}

I've generalised this solution, by using @dtothefp idea of a require array:

client: {
  mocha: {
    ui: 'my-ui',
    require: [ require.resolve('bdd-lazy-var/bdd_lazy_var_global') ]
  }
}

lib/index.js#initMocha

var initMocha = function (files, mochaConfig) {
  files.unshift(createPattern(path.join(__dirname, 'adapter.js')))

  if (mochaConfig.require) {
    for (var requirePath of mochaConfig.require) {
      files.unshift(createPattern(requirePath));
    }
  }

  var mochaPath = path.dirname(require.resolve('mocha'))
  files.unshift(createPattern(path.join(mochaPath, 'mocha.js')))

  if (mochaConfig && mochaConfig.reporter) {
    files.unshift(createPattern(path.join(mochaPath, 'mocha.css')))
  }
}

Also need to exclude the require array from being sent to mocha in the adapter. Will throw a PR together asap.