The presentation design emphasizing the interface between user and web application gives rise to usability testing. The actual user of an application should feel good while using the application and understand every thing visible to him/her on it. Usability testing is not a functionality testing, but the web application is reviewed and tested from a user's viewpoint. The importance of usability testing can be realized with the fact that we can even lose users because of a poor design. For example, check that form controls, such as boxes and buttons, are easy to use, appropriate to the task, and provide easy navigation for the user. The critical point for designers and testers in this attesting is that web application must be as pleasant and flexible as possible to the user.

Usability testing may include tests for navigation. It refers to how the user navigates the web pages and uses the links to move to different pages. Besides this, content should be logical and easy to understand. Check for spelling errors. Use of dark colours annoys users and should not be used in the site theme. You can follow some standards that are used for web page and content building. Content should be meaningful. All the anchor text links should work properly. Images should be placed properly with proper sizes.

For verification of web application, the presentation design must be checked properly so that most of the errors are resolved at the earlier stages only. Verification can be done with a technique called card-sorting technique given by Michael D. Levi and Frederick G. Conrad. According to this technique, a group of end-users are given a set of randomly ordered index cards, each of which is labeled with a

concept from the task domain. The users scatter all the index cards on the desk, and then sort them according to a category. The users arrange these groups in the broader category. They then write a name for each of the larger groupings, on a slip of paper, and attach each slip to the corresponding group. After this process of sorting, the card sort results are compared to the original presentation design of the application. In this comparison, we may find several areas where we can improve the underlying of hierarchy so that users can easily find the information they were looking for.

For validation, a scenario-based usability testing can be performed. This type of testing may take the help of use-cases designed in the use-case model for the system. All the use-cases covering usability points can become the base for designing test cases for usability testing. In this usability testing, some categories of users are invited to perform the testing. The testers meet the group of participants to describe the system in general terms, give an overview of the process, and answer any questions. Participants are seated in front of a desktop computer and asked to work through the scenario questions. At the end of the session, a group discussion is held to note down the participants' reactions and suggestions for improvement. The results of user testing can also be taken from the participants in the form of a questionnaire. As they use the application, they answer these questions and give feedback to the testers in the end. Besides this, web server logs can also be maintained for the session of usage by the participants. It provides the testers with a time-stamped record of each participant's sessions providing an excellent approximation of users'journeys through a site.

The log mining method can be used for improvement in application even alter after the release of the product. The actual user session logs can be recorded and evaluated from the usability point. The general guidelines for usability testing are:

1. Present information in a natural and logical order.
2. Indicate similar concepts through identical terminology and graphics. Adhere to uniform conventions for layout, formatting, typefaces, labeling, etc.
3. Do not force users to remember key information across documents.
4. Keep in consideration that users may be from diverse categories with various goals. Provide understandable instructions where useful. Lay out screens in such a manner. that frequently accessed information is easily found.
5. The user should not get irritated while navigating through the web application. Create visually pleasing displays. Eliminate information which is irrelevant or distracting.
6. Content writer should not mix the topics of information. There should be clarity in the information being displayed.
7. Organize information hierarchically, with more general information appearing before more specific detail. Encourage the user to delve as deeply as needed, but to stop whenever sufficient information has been received.
8. Check that the links are active such there are no erroneous or misleading links.