How to use the yeoman-test.mockLocalConfig function in yeoman-test

// helpers.gruntfile()
before(done => helpers.gruntfile({foo: 'bar'}, done));

// helpers.testDirectory()
helpers.testDirectory(path.join(__dirname, './temp'), () => {
	fs.writeFileSync('testfile', 'Roses are red.');
});

// helpers.mockPrompt()
helpers.mockPrompt(generator, {foo: 'bar'});

// helpers.restorePrompt()
helpers.restorePrompt(generator);

// helpers.mockLocalConfig()
helpers.mockLocalConfig(generator, {foo: 'bar'});

// helpers.createDummyGenerator()
const dummyGenerator = helpers.createDummyGenerator();

// helpers.createGenerator()
const angularGenerator = helpers.createGenerator('angular:app', [
	'../../app',
	'../../common',
	'../../controller',
	'../../main',
	[helpers.createDummyGenerator(), 'testacular:app']
]);

// helpers.registerDependencies()
helpers.registerDependencies(env, ['dependency']);