I have my 99$ subscription in apple developers portal my doubt is that for how many different devices i can test my application, is there any limitations say you can test in 10 different devices?
You can test with up to 100 devices per year.
This is to prevent developers from selling their apps outside the app store by using the developer certificate and registering an endless number of devices.
Even if you remove a device from the list, it will still count towards your 100 devices per year limit.