Pass an argument to Gulp to only run a subset of Specs

gulpfile.js

"use strict";
const gulp = require('gulp'),
      mocha = require('gulp-mocha'),
      minimist = require('minimist');

const knownOptions = {
    string: 'spec',
    default: { spec: '*' }
};

const options = minimist(process.argv.slice(2), knownOptions);

gulp.task('test', ['hint'], () => {
    return gulp.src([`test/**/${options.spec}Spec.js`], {read: false}) // String interpolation FTW!
        .pipe(mocha());
});

gulp.task('default', ['test']);

usage-from-cli.sh

$ gulp test --spec foo