Installation testing services are mostly used to verify whether a program or a system is installed successfully and with all necessary components, and is working as intended after installation. Also, these come in useful when software is updated or retired.  

Nowadays, there is a popular tendency among most app users, to setup software using installers (specialized programs that themselves also need to be thoroughly tested). However, you can hardly find installers in real life. Then, you may have to install a software program using the documentation such as instructions or README files which step by step describe all the necessary actions and testing processes.

Pen testing services are worth considering when it comes to securing private data. They help to restrict unauthorized access from external networks. Protect your database from insider attacks and ensure data privacy.

In a distributed system, where the app is deployed directly to production environment, just a simple set of instructions may be not enough to understand the principle that governs internal workings of the systems. That is why relevant specialists create Deployment Plan, which includes not only the steps to install the software, but also the steps to rollback to an earlier version of the program, in case of failure to complete the setup process. The deployment plan itself must also be tested in order to avoid problems during the operation period, when the product becomes available for use. This is especially true if you are installing a system because in this case every minute of downtime can cause reputation damage and loss of too many valuable tools such as finance companies, banks or even banner networks. For that reason, installation testing can be referred to as a one of the most important processes to ensure the best quality of software products.

This very comprehensive approach to quality assurance along with writing plans, testing software installation or the app after rolling back the changes can be rightfully called as Installation Testing. This verification should be performed for every new software build, new version of a program or a software app that underwent modifications.

Please, be advised that selenium testing services can be helpful for verifying web applications. Selenium is a open source test automation suite for web apps across a variety of browsers and platforms.