How to use the yeoman-generator.assert.fileContent function in yeoman-generator

it('save skipBootstrap to configs', function () {
      assert.fileContent('.yo-rc.json', /"withBootstrap": false/);
    });

it('test contains AMD path', function() {
      assert.fileContent('test/apps/apples/apples_composite_view_test.js', /apples_composite_view/);

    });
    it('test contains compositeview class', function() {

it('contains task configuration', function() {
        assert.fileContent('grunt-tasks/config/styles.js', /grunt\.config\('less'/);

        assert.fileContent('grunt-tasks/config/styles.js', /\/styles\/main\.less/);
        assert.fileContent('grunt-tasks/config/watch.js', /\.less/);

        assert.fileContent('grunt-tasks/register/styles.js', /less/);
      });

it('test with right content ', function() {
      assert.fileContent('app/scripts/apps/apples/apples_composite_view_test.js', /.\/apples_composite_view/);
      assert.fileContent('app/scripts/apps/apples/apples_composite_view_test.js', /, ApplesCompositeView/);
      assert.fileContent('app/scripts/apps/apples/apples_composite_view_test.js', /new ApplesCompositeView/);
    });
    it('test contains Mocha syntax', function() {

it('should have mongo connect', function () {
            assert.fileContent('server/server.js', 'mongoose.connect(config.mongo.uri, config.mongo.options);');
        });

it('should check the package tests dependencies', function () {
            assert.fileContent('package.json', 'mocha');
            assert.fileContent('package.json', 'karma');
            assert.fileContent('package.json', 'phantomjs');
            assert.fileContent('package.json', 'jasmine');
            assert.fileContent('package.json', 'protractor');
            assert.fileContent('package.json', 'should');
            assert.fileContent('package.json', 'supertest');
            assert.fileContent('package.json', 'jscs');
            assert.fileContent('package.json', 'jshint');
        });

it('save configs of bootstrap', function () {
      assert.fileContent('.yo-rc.json', /"withBootstrap": true/);
    });

gen.onEnd(function() {
			assert.fileContent('Gruntfile.js', /availabletasks/);
			assert.fileContent('Gruntfile.js', /wiredep/);
			assert.fileContent('Gruntfile.js', /clean/);
			assert.fileContent('Gruntfile.js', /copy/);
			assert.fileContent('Gruntfile.js', /ngAnnotate/);
			assert.fileContent('Gruntfile.js', /useminPrepare/);
			assert.fileContent('Gruntfile.js', /usemin/);
			assert.fileContent('Gruntfile.js', /browserSync/);
			assert.fileContent('Gruntfile.js', /jshint/);
			assert.fileContent('Gruntfile.js', /watch/);
			assert.fileContent('Gruntfile.js', /rev/);
			assert.fileContent('Gruntfile.js', /csslint/);
			assert.fileContent('Gruntfile.js', /plato/);
			assert.fileContent('Gruntfile.js', /less/);
			assert.fileContent('Gruntfile.js', /imagemin/);
			assert.fileContent('Gruntfile.js', /htmlmin/);

			assert.noFileContent('Gruntfile.js', /karma/);
			assert.noFileContent('Gruntfile.js', /sass/);

			assert.fileContent('Gruntfile.js', /grunt\.registerTask\('report', \[\s+'plato',\s+ 'connect:plato'\s+\]\)/);
			assert.fileContent('Gruntfile.js', /grunt\.registerTask\('dev', \[\s+'less',\s+'browserSync',\s+'watch'\s+\]\)/);
			assert.fileContent('Gruntfile.js', /grunt\.registerTask\('package', \[\s+'jshint',\s+'clean',\s+'useminPrepare',\s+'copy',\s+'concat',\s+'ngAnnotate',\s+'uglify',\s+'less',\s+'cssmin',\s+'rev',\s+'imagemin',\s+'usemin',\s+'htmlmin'\s+\]\)/);
			assert.fileContent('Gruntfile.js', /grunt\.registerTask\('ci', \[\s+'package',\s+'plato'\s+\]\)/);
			assert.fileContent('Gruntfile.js', /grunt\.registerTask\('ls', \['availabletasks'\]\)/);

assert.fileContent('Gruntfile.js', /useminPrepare/);
			assert.fileContent('Gruntfile.js', /usemin/);
			assert.fileContent('Gruntfile.js', /browserSync/);
			assert.fileContent('Gruntfile.js', /jshint/);
			assert.fileContent('Gruntfile.js', /watch/);
			assert.fileContent('Gruntfile.js', /rev/);
			assert.fileContent('Gruntfile.js', /csslint/);
			assert.fileContent('Gruntfile.js', /plato/);
			assert.fileContent('Gruntfile.js', /less/);
			assert.fileContent('Gruntfile.js', /imagemin/);
			assert.fileContent('Gruntfile.js', /htmlmin/);

			assert.noFileContent('Gruntfile.js', /karma/);
			assert.noFileContent('Gruntfile.js', /sass/);

			assert.fileContent('Gruntfile.js', /grunt\.registerTask\('report', \[\s+'plato',\s+'connect:plato'\s+\]\)/);
			assert.fileContent('Gruntfile.js', /grunt\.registerTask\('dev', \[\s+'less',\s+'browserSync',\s+'watch'\s+\]\)/);
			assert.fileContent('Gruntfile.js', /grunt\.registerTask\('package', \[\s+'jshint',\s+'clean',\s+'useminPrepare',\s+'copy',\s+'concat',\s+'ngAnnotate',\s+'uglify',\s+'less',\s+'cssmin',\s+'rev',\s+'imagemin',\s+'usemin',\s+'htmlmin'\s+\]\)/);
			assert.fileContent('Gruntfile.js', /grunt\.registerTask\('ci', \[\s+'package',\s+'plato'\s+\]\)/);
			assert.fileContent('Gruntfile.js', /grunt\.registerTask\('ls', \['availabletasks'\]\)/);

			done();
		});
	});

.on('end', function() {
        assert.file('package.json');
        assert.fileContent('package.json', /babel-preset-stage-0/);
        assert.fileContent('package.json', /babel-preset-stage-0/);
        assert.fileContent('package.json', /babel-plugin-transform-strict-mode/);
        assert.fileContent('package.json', /babel-plugin-transform-object-assign/);
        done();
      });
  });