AutoFixture.js

AutoFixture.js is based off of Mark Seeman's AutoFixture for .NET. The AutoFixture.js syntax attempts to match that of AutoFixture as much as possible where reasonable. You'll find the syntax and functionality applicable to JavaScript very similar and easy to understand.

Quick Start

For the examples below, I'm going to assume that autofixture has already been require'd and assigned to the fixture variable.

General Syntax

The general syntax provided by AutoFixture.js follows:

var fixture = require('autofixture');
var instance = fixture.Create(ConstructorFunction[, args]);

What that means is that most of the constructor functions for the builtin JavaScript types are available.

String Creation

To create a string we'd do the following:

var myString = fixture.create(String);
// myString will look like a guid, e.g., '44CDC249-EAA2-4CC4-945C-B52475B0B0A9'

As with AutoFixture, we can also create a string that's prefixed by a value of our choosing. That's done by passing in a string:

var prefixedString = fixture.create('prefix');
// myString will look like a guid with our prefix. e.g.: 'prefix44CDC249-EAA2-4CC4-945C-B52475B0B0A9

Number Creation

To create a Number we'd do the following:

var myNumber = fixture.create(Number);
// myNumber will be a number between [0, 1). E.g., 0.59147235396

If we'd like a negative number or a larger number we can provide a multiplier:

var myNegativeNumber = fixture.create(Number, -1);
// myNegativeNumber will be between (-1, 0]. E.g., -0.7982537387376
var myLargeNumber = fixture.create(Number, 500);
// mylargeNumber will be between [0, 500). E.g., 423.8746491657
var myLargeNegativeNumber = fixture.create(Number, -700);
// myLargeNegativeNumber will be between (-700, 0]. E.g., -672.451987454916

Boolean Creation

To create a Boolean we can do the following:

var myBoolean = fixture.create(Boolean);
// myBoolean will be either true or false.

Object Creation

Creation From a Like Object

In JavaScript we frequently use objects and object literals and care not whether the object was created with a constructor function. AutoFixture.js handles this by using a provided object as a template, or specimen, for the object to be created.

To create an object that's similar to an existing object, just pass the object in to the create method:

var myObj = fixture.create({prop1:'a string', prop2: 1.234, prop3: true});
/*
myObj will look something like the following: 
{
  prop1: 'prop121032407-9216-404A-9F6A-021E8766AF21',
  prop2: 0.2518655981465,
  prop3: true
}
*/

Each of the property values are randomly chosen from the set of allowable values. In the case of properties that are of type string the string value will be prefixed by the property name to allow the values to be easily distinguishable.

Creation From a Constructor Function

Just as the builtin constructor functions can be used to create strings, numbers, and booleans, custom constructor functions can be used to create other objects.

function MyObjectType() {
    this.prop1 = '';
    this.prop2 = '';
    this.prop3 = 0;
    this.prop4 = false;
}
var myObj = fixture.create(MyObjectType);
/*
myObj will look something like the following:
{
  prop1: 'prop121032407-9216-404A-9F6A-021E8766AF21',
  prop2: 'prop27237F916-AAB4-40CF-814E-8BEC7181A70C',
  prop2: 0.98712634589712,
  prop3: true
}
*/

As with Like-Object creation described above, the instance values are assigned based on their respective property types. Because prop and prop2 are strings, they were assigned random values prefixed by the property name.