From time to time, we need to test something in our infrastructure. Production is not good idea for this, so we build a test environment. Sometimes, such tests may require changes in the hypervisor, which we want to avoid in the production. In such cases, we can work on dedicated test hardware or we can virtualize. Virtualization nesting can be helpful for development, getting familiar with new technologies, new product versions or learning purposes where we can easily simulate our production environment. In this article, we'll explore how to build the test environment on different platforms with help of nested virtualization.