mock-fs module test example

app.js

// endsWidth, see http://stackoverflow.com/questions/280634/endswith-in-javascript
String.prototype.endsWith = function(suffix) {
    return this.indexOf(suffix, this.length - suffix.length) !== -1;
};

var fs = require('fs'),
  path = require('path'),
  mock = require('mock-fs');

function showText(file) {
  if ( file.endsWith(".txt") ) {
    console.log(file, "=>", fs.readFileSync(file, {
      encoding: 'utf-8'
    }));
  }
}
function readDir(dir) {
  if ( !dir ) dir = __dirname;
  var files = fs.readdirSync(dir);
  console.log(dir, "=>", files);
  
  for ( var i = 0; i < files.length; i++ ) {
    if ( files[i] == "node_modules" ) continue;
    var subDir = path.join(dir, files[i])
    var stat = fs.statSync(subDir);
    if ( stat.isDirectory() ) {
      readDir(subDir);
    } else {
      showText(subDir);
    }
  }
}

(function main(){
  console.log("REAL");
  readDir();
  
  console.log("MOCK");
  mock({
    'mock.txt': 'MOCK!',
    'home/': {
      'subfolder': {
        'welcome.txt': 'Welcome to the mock-fs.'
      }
    }
  });
  readDir();
  
  mock.restore();
  console.log("REAL");
  readDir();
}());