The nature of test environments is inherently temporary—you set up an environment, run through an automated test suite, and then tear down the environment. If you can reduce the cycle time for this process down to hours or minutes, then you may be able to cut your test environment budgets considerably.
The impact of cloud adoption on test environments is a valuable advancement in both cost savings and agility. The on-demand model takes advantage of public cloud APIs requiring only payment for the time needed to run automated tests. In this framework, success depends on two things: automated infrastructure and automated acceptance tests. If these two goals can be achieved, the cost savings from reduced infrastructure spend and the increase in agility will more than pay for the cost of both automation initiatives.