Instantiating a controller that uses an isolate scope for a test - angularjs

Question

So I have a controller test file with:
scope = $rootScope.$new();
ctrlInstance = $controller( 'formCtrl', { $scope: scope } );
This controller isn't getting instantiated correctly, because the scope that I'm passing in doesn't have data that it normally has (due to being passed from an isolate scope).
These are the first few lines of my formCtrl:
var vm = this;
vm.stats = angular.copy( vm.statsStuff );
vm.stats.showX = vm.stats.showY = true;
Note that vm.statsStuff has data bound to it (due to a '=' scope in the corresponding directive), but I'm not sure how to pass it these values when I instantiate my controller in the test.
Any help would be appreciated.
Adding directive:
angular.module( 'myModule' )
.directive( 'formStuff', function() {
return {
restrict: 'E',
templateUrl: 'dir.tpl.html',
scope: {
statsStuff: '='
},
controller: 'formStuffCtrl',
controllerAs: 'formCtrl',
bindToController: true
};
} );
})();

Answer 1

The angular-mocks module has a $controller service that decorates the "real" one, and allows passing a third argument, containing data to bind to the controller before instantiating it.
So all you should need is
ctrlInstance = $controller('formCtrl', { $scope: scope }, { statsStuff: theStuff } );

Answer 2

Until you upgrade to 1.4 (when doing so, JB's answer is the way), I would do the following to "emulate" what the third parameter is doing (to some extent*):
var $scope, ctrlInstance, createController;
beforeEach(function () {
module('your_module');
inject(function ($injector, $controller) {
$scope = $injector.get('$rootScope').$new();
createController = function (bindStuff) {
ctrlInstance = $controller('formStuffCtrl', {
$scope: $scope
});
Object.keys(bindStuff).forEach(function (key) {
ctrlInstance[key] = bindStuff[key];
});
});
});
});
it('exposes the "statsStuff stuff"', function () {
var stats = { x: 500, y: 1000 };
createController({ stats: stats });
expect(ctrlInstance.stats).to.deep.equal(stats);
});
Even without the bindToController 'emulation', I would highly recommend the createController way of instantiating your controller as it gives you the flexibility of manipulating the controllers dependencies before hand (without the need of another before|beforeEach block).
*: I say to some extent, as this is attaching the properties after the controller has been instantiated, whereas bindToController attaches the properties before hand. So there may very well be some discrepancies between the two.