Doubler

Simple test doubles and stubs for NodeJS testing purposes, designed for usage when tools like Sinon offer more power than your project needs.

``sh
npm install --save-dev doubler
`

Documentation

Until I am able to write up proper docs, the best place to look is the test file, which shows the API nicely.

Doubles

$3

Useful when you need to pass an object in that contains multiple methods:

`js
var Double = require('doubler').Double;
var double = new Double({
// either give it a function to call
foo: function() { return 2 },
// or just a single value
bar: 3
});
double.foo(); //=> 2
double.bar(); //=> 3
double.foo.called; //=> true
double.foo.callCount; //=> 1
double.foo('bar');
double.foo.args; //=> [[], ['bar']]

// reset the double, as if it had never been called
double.foo.reset(); //=> resets double back to new state
double.foo.called; //=> false
`

$3

Often you don't want to create an object with doubles on it but generate just a function:

`js
var doubleFn = Double.function(2);
doubleFn(); //=> 2
doubleFn.called; //=> true
doubleFn.callCount; //=> 1
doubleFn.args; //=> [[]]
`

You can also give a custom function to call rather than a single return:

`js
var doubleFn = Double.function(function() {
return 3;
});
doubleFn(); //=> 3
doubleFn.called; //=> true
doubleFn.callCount; //=> 1
doubleFn.args; //=> [[]]
`

Stubs

`js
var Stub = require('doubler').Stub;

// some object with a method we'd like to stub:
var Foo = {
get: function() { return 2; }
}

new Stub(Foo, 'get').returnValue(4);
Foo.get(); //=> 4
Foo.get(); //=> 2 (Spies only last for one invocation by default)

new Stub(Foo, 'get').callFunction(function() {
return 5;
});
Foo.get(); //=> 5

// call persist() to make a stub last forever
var stub = new Stub(Foo, 'get').persist().returnValue(4);
Foo.get(); //=> 4
Foo.get(); //=> 4
Foo.get(); //=> 4 and so on

// entirely remove the stub
stub.destroy();
Foo.get(); //=> 2
`

Under the hoods stubs actually use doubles, so all the properties on a double that you can use to check invocations are also available on stubs:

`js
var Stub = require('doubler').Stub;

// some object with a method we'd like to stub:
var Foo = {
get: function() { return 2; }
}

new Stub(Foo, 'get').returnValue(4);
Foo.get(); //=> 4
Foo.get.called; //=> true
Foo.get.callCount; //=> 1
Foo.get.args; //=> [[]]
`

Changelog

#### V0.6.0
- provide Double.function for creating standalone function doubles

#### V0.5.0
- Proxy properties from a Stub's underlying double through. You can now call args, callCount and called on a stub.

#### V0.4.0
- add #reset` method to doubles to allow them to be set back to blank

#### V0.3.0
- doubles keep track of their arguments

#### V0.2.1
- pass arguments through to stubbed functions

#### V0.2.0
- added basic Stubs

#### V0.1.0
- initial release