simple-mock

simple-mock

Super simple mocks, stubs, and spies with 1-step sandbox restore.

Install

npm install simple-mock

Mock

You can mock any function or value on an object and easily restore it.

Examples

simple.mock(obj, 'example', 'value'); // Replace with this value
simple.mock(obj, 'example', function() {}); // Replace with this function

simple.mock(obj, 'example') // Spy on underlying method *or* stub
simple.mock(obj, 'example').callbackWith(null, 'etc'); // Stub
simple.mock(obj, 'example').returnWith('etc'); // Stub
simple.mock(obj, 'example').throwWith(new Error()); // Stub

Then, to make sure all objects are back to the state the were in before your mocks:

simple.restore(); // Ideally called in an afterEach() block

callbackWith, returnWith and throwWith can be chained for queued behaviour, e.g.

simple.mock(Something.prototype, 'example')
  .callbackWith(null, 'etc')
  .callbackWith(new Error());

callbackWith, returnWith and throwWith configurations are stored on a simple array fn.actions

Expectations

You define your expectations with your own choice of assertion library.

assert(fn.called);
assert.equals(fn.callCount, 3);
assert.equals(fn.lastCall.args[0], error); // First parameter of the last call
assert.equals(fn.calls[0].returned, 'etc');
assert.equals(fn.calls[1].threw, error);

Standalone Stubs and Spies

If you need to create a standalone stub (stubs are also spies):

simple.stub().callbackWith(null, 'etc');
simple.stub().returnWith('etc');
simple.stub().throwWith(new Error());

Or spy on a standalone function:

var fn = simple.spy(function(){});

assert.equals(fn.callCount, 0);
assert.equals(fn.calls, []);