Mock a $stage.go transition - angularjs

Question

I have a controller with an activate() method:
function CustomerController(customerFactory, $state, $stateParams) {
var vm = this;
vm.getCustomer = getCustomer;
activate();
function activate() {
if($state.is('customer-view')) vm.getCustomer($stateParams.id);
}
function getCustomer(id) {
return customerFactory.getCustomer(id)
.then(getCustomerComplete)
.catch(getCustomerFailed);
function getCustomerComplete(response) {
return vm.customer = response;
}
function getCustomerFailed(error) {
return vm.error = error;
}
}
}
I want to test, using jasmine, that on $state.go('customer-view', {id: 1}) the getCustomer(id) function has been called.
Here is my test:
it("should be called", inject(function($state) {
spyOn(vm, 'getCustomer');
$state.go('customer-view', {id: 1});
expect(vm.getCustomer).toHaveBeenCalledTimes(1);
}));
And the test returns "Expected spy getCustomer to have been called once. It was called 0 times."
PS: the code above is working, I just don't know how to test it.
EDIT:
Here a bigger example of my spec file:
describe("app.customers controller", function () {
var $controller, customers, deferred, customerFactoryMock, vm, $rootScope, $q;
beforeEach(function () {
module('app.customers');
});
beforeEach(inject(function (_$rootScope_, _$controller_, _$q_, _customerFactory_) {
customerFactoryMock = _customerFactory_;
$controller = _$controller_;
vm = $controller("CustomerController", {customerFactory: customerFactoryMock});
$q = _$q_;
deferred = $q.defer();
$rootScope = _$rootScope_;
customers = [{"id": 1}, {"id": 2}];
}));
describe("getCustomer(id)", function () {
it("should call the factory method", function () {
spyOn(customerFactoryMock, 'getCustomer').and.returnValue(deferred.promise);
vm.getCustomer(1);
expect(customerFactoryMock.getCustomer).toHaveBeenCalledTimes(1);
});
it("should be called", inject(function($state) {
spyOn(vm, 'getCustomer');
$state.go('customer-view', {id: 1});
expect(vm.getCustomer).toHaveBeenCalledTimes(1);
}));
it("should have a customer on resolved", function () {
spyOn(customerFactoryMock, 'getCustomer').and.returnValue(deferred.promise);
deferred.resolve({"id": 1});
vm.getCustomer(1);
$rootScope.$digest();
expect(vm.customer).toBeDefined();
expect(vm.customer.id).toEqual(1);
});
it("should return an error message on reject", function () {
spyOn(customerFactoryMock, 'getCustomer').and.returnValue(deferred.promise);
deferred.reject('this is a reason');
vm.getCustomer();
$rootScope.$digest();
expect(vm.error).toBeDefined();
expect(vm.error).toBe('this is a reason');
});
});
});