The mobile device is a system, that has not powerful stuffing. So, it can not work as a personal computer.
The mobile application testing in provided on handsets ( Apple, Samsung, Nokia, etc.), while the desktop app is tested on a central processor.
Mobile devices screens variety, their extensions, and colors. Mobile phone screen size is smaller than desktop ones.
Making and receiving calls is the main task of the phone, that is why the application should not interfere with this major function.
A wide variety of specific operating systems and component configurations: Android, iOS, BlackBerry
Mobile phone OS quickly becomes obsolete. In addition, there is a limit to updating their OS.
Mobile devices use network connections ( 3G, 4G, Wi-Fi), desktop use broadband connection or Wi-Fi.
Mobile devices constantly search the network. That is why you should test the application at different data rates.
Tools, which are good for the desktop apps testing, are not fully suitable for the mobile application testing.
Mobile applications must support multiple input channels (keyboard, voice, gestures, etc.), multimedia technologies and other features that increase their usability.