What are different stages involved in web application testing?

Web application is a dynamic extension of an application server. Testing of a web application is done by a web application tester. Testing a web application involves different stages as follows:

Functionality testing:
In functionality testing, tests are made to check the links in web pages, database connection, forms used in web pages to submit or retrieve information from users.

Testing the links involves the following:
- Checking the outgoing links in all the pages from the specific domain under test.
- Internal links testing.
- Checking the links that jump on the same pages.
- The Links through which the email will be sent to the admin or to other users from different web pages must be checked.
- All the above mentioned links must be checked for broken links.

Testing the forms in all the web pages:
- Each field in a form must be checked for validity.
- Default values of each field must be checked.
- Options for creating, modifying, viewing or deleting a form must be verified during testing.

Testing of cookies:
The application must be tested by enabling or disabling cookies in browser options. The cookies must be tested for encryption before writing to user system. The session cookies must be tested for login sessions and user status after session ends.

Testing of database:
Data integrity must be monitored every time when data is created, modified, viewed or deleted within a database. Every database related functionality must be tested.

Usability testing:
Usability determines the ease with which a user can handle the application. The webpage designed must be user friendly with appropriate main menu in each page. It is very important to ensure that the application is readable and understandable by a user. It is recommended to use commonly accepted standards for font, frames and colors. Anchor text links must be analyzed.

Interface testing:
Web server, application server and database server are the main interfaces. Ensure whether each interaction between each of the interfaces is executed without any errors. Errors when occurred must be handled appropriately.

Compatibility testing:
Compatibility of a web application is a very important testing aspect. A web application must be compatible mainly with Browser and Operating System.

Browser compatibility:
A web application must be tested with different browsers to ensure its compatibility. Various browsers have different settings and configurations with which the application must be compatible. Web coding must be compatible with cross browser platform. If java scripts or AJAX calls are used for UI functionality and performing security checks or validations, browser compatibility must be given importance.

OS compatibility:
New technologies such as graphic designs, interface calls used in web development must be compatible with various browsers, which are popularly used.

Performance testing:
Performance of an application is measured by its ability to sustain load and stress. Load testing and stress testing are two main types of performance testing.

Load testing:
When large number of users requests the same page, the application must have the ability to sustain the load and perform appropriately. Performance of an application must be tested on different internet connections with varying speed.

Stress testing:
In stress testing the application is put beyond its limit of sustainability, to check the reaction of the application to stress or to check how the system recovers from crash.

Security testing:
Security testing must ensure that only authorized users can use the application and none of the internal pages must be opened for non registered users. CAPTCHA can be utilized to improve security in application.