feat: pass command line arguments for `start` command

Following on from #530

We now have:

$ karma start &
$ karma run -- --grep someTest

But that sucks for batch runs (like CI scripts), because you need to:

• run karma start
• parse its output (!) to see when it’s ready
• run karma run -- <args>
• kill the first process
• deal with other messy stuff related to managing multiple processes

There is real need for this feature, e.g segmenting travis builds by test type:

• karma start --single-run -- --tag unit
• karma start --single-run -- --tag integration

Options:

• treat everything after -- as clientArgs, just like we do for run. @vojtajina doesn’t like this, because it removes the possibility of using this for something else in the future.
• an explicit --client-args would trigger that ALL following arguments should be taken as clientArgs: karma start --single-run --client-args --grep unit This should probably grab only up to the next “–” argument though.
• more tediously, specifying them individually: karma start --single-run --client-arg=--grep --client-arg=unit

Other suggestions?

[danielsiwiec]

@gaelazzo @timbertson A bit late to the party, but since this there’s a much simpler solution now:

karma start --grep integration

karma.conf.js:

module.exports = function (config) {
  config.set({
    ...,
    client: {
      args: ['--grep', config.grep]
    }
  })
}

[vojtajina]

Put it to the config file, exactly as you do with any other config variable.