Mute Yeoman while tests run (see https://github.com/yeoman/generator/issues/472)

mute.coffee

###
	Silence STDOUT & STDERR streams during tests
	Useful for Yeoman to provide a cleaner output
	@uses github.com/balderdashy/fixture-stdout

	Yeoman Usage:
	If your generator logs anything on the 'end' event
	you can add an additional event as the very last
	thing and trigger Output.unmute() on that event instead.
	```
	# app.spec.coffee
	Output = require( '../utils/mute' );

	beforeEach ->
		# ...
		@app.on( 'start', Output.mute );
		@app.on( 'end', Output.unmute );
	```
###

'use strict'

Fixture    = require( 'fixture-stdout' )
fixtureOut = new Fixture(  )
fixtureErr = new Fixture( stream: process.stderr )
_writesOut = []
_writesErr = []

# Mute
module.exports.mute = ->
	fixtureOut.capture onWrite = (string, encoding, fd) ->
		_writesOut.push string: string

		# Prevent original write
		return false

	fixtureErr.capture onWrite = (string, encoding, fd) ->
		_writesErr.push string: string

		# Prevent original write
		return false


# Unmute
module.exports.unmute = ->
	fixtureOut.release(  )
	fixtureErr.release(  )


# Return the output that was captured
module.exports.getMutedWrites = ->
	out: _writesOut
	err: _writesErr

mute.js

/**
 * Silence Yeoman during tests
 * uses github.com/balderdashy/fixture-stdout
 *
 * Usage:
 * ```
 * // test-something.js
 * var Output = require( './mute' );
 *
 * // beforeEach() test:
 * this.app.on( 'start', Output.mute );
 * this.app.on( 'end', Output.unmute );
 * ```
 */

'use strict';


var Fixture    = require( 'fixture-stdout' );
var fixtureOut = new Fixture(  );
var fixtureErr = new Fixture({ stream: process.stderr });

var _writesOut = [];
var _writesErr = [];


// Mute
module.exports.mute = function (  ) {
	fixtureOut.capture( function onWrite ( string, encoding, fd ) {
		_writesOut.push({ string : string });

		// Prevent original write
		return false;
	});


	fixtureErr.capture( function onWrite ( string, encoding, fd ) {
		_writesErr.push({ string : string });

		// Prevent original write
		return false;
	});
};


// Unmute
module.exports.unmute = function (  ) {
	fixtureOut.release();
	fixtureErr.release();
};


// Return the output that was captured
module.exports.getMutedWrites = function (  ) {
	return {
		out: _writesOut,
		err: _writesErr
	};
};

test-something.js

'use strict';

var Output = require( './mute' );

describe('My generator', function (  ) {
	beforeEach(function ( done ) {
		helpers.testDirectory(path.join( __dirname, 'temp' ), function ( err ) {

			this.app = helpers.createGenerator('mygenerator:app', [
				'../../app'
			]);

			// Prevent Yeoman writes while the generator runs
			// and reenable them when it's finished to see the test results
			this.app.on( 'start', Output.mute );
			this.app.on( 'end', Output.unmute );

			done(  );

		}.bind( this ));
	});
});

Thanks for this. I hope there will be an official solution soon.