Design guidelines for mobile usability testing
There are certain unique priorities in mobile application testing. These priorities greatly affect the usability of the program and the quality of user experience and as such must be tested for. The first is font size, mobile devices have far less screen space than laptops or desktops. This makes font size of critical importance. The fonts should not be so big that a large amount of scrolling is required, nor should they be so small that they're hard to read. Mobile applications have a restricted number of useful fonts, while desk or laptop applications can use pretty much any font. Mobile applications should use the simplest and easiest to read font possible.
Another important aspect is to test for information presentation. Small screen size makes reading a large amount of information difficult and slow. Consequently, information should be tiered with the most important information up front, this is especially true of information that helps the user make a decision. In fact, all information should be graded for importance and presented accordingly.
Quality of presentation is another important aspect for testing. Mobile devices are often used on the run, with the user's attention divided by multitasking. This means that users do not always have a large amount of attention to spend, combine this with the small size of the screen and it's very easy to miss information. Consequently, presentation should be designed so that information can be read in quick bites and screen contrast should be such that the screen can be read in different lighting situations with relative ease.
Data entry is also another important area for testing. No mobile application should require a large amount of data entry, it simply isn't practical with the device in hand. There are a number of ways to minimize data entry, such as presenting predetermined lists of actions. While navigation should be simple and easy to understand. Mobile applications should also be tested to ensure that there is always a way for the user to exit from any mistake without difficulty. A back button must be easily visible on every page and no user should be required to go down a path from which he or she cannot escape.
Mobile app usability is at its best when it focuses on key functionality and clear and concise content. So it's important to test for consistent user experience throughout the application, regardless of screen orientation or what page of the application the user may be on. Ideally, each page of the application should concentrate on a single action with drop down menus placed discreetly but with easy access.
Finally, the application should function smoothly across all target devices. It's up to the designers and developers to make certain that the application runs well across different platforms and the user interface is easily understood, attractive and usable on every device that the application is intended to run on.