Angular unit testing with Jasmine: how to remove or modify spyOn
You can just overwrite it
updateService.getUpdate = jasmine.createSpy().and.returnValue(etc)
You can override the return value of the spy
var deferred = $q.defer();
deferred.resolve( data1 );
var getUpdateSpy = spyOn(updateService, 'getUpdate').and.returnValue(deferred.promise);
var newDeferred = $q.defer();
newDeferred.resolve( data2 );
getUpdateSpy.and.returnValue(newDeferred.promise);