# karma-sharding

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> Karma plugin to allow tests to be distributed across multiple browsers

## Notes

This is intended to avoid the memory usage problems seen with some browsers and numerous or memory intensive specs.
Lower your concurrency setting if total memory is a problem running in parallel processes.

You can pass configuration to override these defaults:

```javascript
{
  sharding: {
    specMatcher: /(spec|test)s?\.js/i,
    base: '/base',
    getSets: function(config, basePath, files) {
        // splitForBrowsers - some util function
        return splitForBrowsers(files.served)
            .map(oneBrowserSet => [someInitScript].concat(oneBrowserSet));
    }
  }
}
```
`getSets` might be overridden when files from `karma.files` config should be organized in certain view, for example:

`karma.files` has set - `[setup.js, one.unit.js, two.unit.js]` - and it must be combined for each browser as `[setup.js, one.unit.js]` and `[setup.js, two.unit.js]`

## Installation

The easiest way is to install `karma-sharding` as a `devDependency`,
by running

```bash
npm install karma karma-sharding --save-dev
```

## Examples

### Basic

```javascript
// karma.conf.js
module.exports = function(config) {
  config.set({
    files: [
      'src/**/*.js',
      'test/**/*.js'
    ],

    frameworks: ['sharding'], // this will load the framework and beforeMiddleware

    preprocessors: {
      // source files, that you wanna generate coverage for
      // do not include tests or libraries
      // (these files will be instrumented by Istanbul)
      'src/**/*.js': ['coverage'] // coverage is loaded from karma-coverage by karma-sharding
    },

    // sharding replaces the coverage reporter inline to allow the preprocessor to run
    // preprocessor:coverage looks for reporter:coverage otherwise it would use a unique name
    reporters: ['progress', 'coverage'],

    browsers: ['ChromeHeadless', 'ChromeHeadless'] // this will split the tests into two sets
  });
};
```

----

For more information on Karma see the [homepage].


[homepage]: http://karma-runner.github.com