According to the definition, cookie is a text file with small scope of information that is saved on a hard disk of a user. Usually, cookies include information needed for web browser operation, for example, emails, passwords, session tokens etc.

Such data help a web browser to identify a user and monitor his navigation on the Internet.

Types of cookies:

• Sessions cookies, known as well as in-memory cookies or transient cookies, are cookies that expire when web browser is closed. They are saved in temporary memory and when the session is over, cookies are deleted automatically.
• Persistent cookies, unlike session cookies, have long term of storage that helps a web browser to record information about users and after some period of time create their profiles. Such cookie can be deleted manually or when its term expires.

For many modern websites cookies play an important role, so while website testing specialists give particular attention to cookies work.

How to сheck сookies by website testing:

• Cookies can be used effectively by e-commerce testing. For example, a user added several items to the shopping cart and closed the web browser after that. Software testers check whether chosen products are saved, when user goes back to the website.
• By software testing cookies help to monitor quantity of unique users for particular period of time.
• At customized websites users have a possibility to choose which pages to show and which to forbid. This information is saved in cookies.
• It is important to check whether personal or confidential information like credit card number or user credentials is saved in cookies. If yes, the data should be encrypted. That is security issue.
• The website should store cookies properly on different browsers, so it should be verified while cross-browser testing.
• Cookies disabling can lead to crash or incorrect behavior of the website. If cookies are necessary for proper functionality of the resource, the message like: “For smooth running of the website, please, make sure that Cookies are enabled”.

In general, cookies are of great importance by functionality, load or performance testing, since it is one of the main parts of a website that concerns user’s security and convenience.