Angular Mock for properly resolving ui-router $state in Karma unit tests

stateMock.js

angular.module('stateMock',[]);
angular.module('stateMock').service('$state', function ($q) {
    this.expectedTransitions = [];
    
    this.transitionTo = function(stateName) {
        if(this.expectedTransitions.length) {
            var expectedState = this.expectedTransitions.shift();
            
            if (expectedState !== stateName) {
                throw Error('Expected transition to state: ' + expectedState + ' but transitioned to ' + stateName);
            }
        } else {
            throw Error('No more transitions were expected! Tried to transition to ' + stateName);
        }
        
        console.log("Mock transition to: " + stateName);
        
        var deferred = $q.defer();
        var promise = deferred.promise;
        deferred.resolve();
        
        return promise;
    };
    this.go = this.transitionTo;
    
    this.expectTransitionTo = function (stateName) {
        this.expectedTransitions.push(stateName);
    };

    this.ensureAllTransitionsHappened = function () {
        if (this.expectedTransitions.length) {
            throw Error('Not all transitions happened!');
        }
    };
});