What is an alternative flow (alternative scenario)?

An alternative flow is a variation of events during the use of a system, which differs from the main (primary) flow but is also possible and should be considered.

For example, in the process of placing an order in an online store, the main scenario is that the user successfully adds a product to the cart and pays for the order. An alternative scenario is that the user enters incorrect card details, and the system prompts to correct the error.

In testing, alternative scenarios help verify how the system behaves in non-standard or erroneous situations, ensuring reliability and user convenience.