Test screenings are just one small part of the entire expansive film production process, but oftentimes, they can be one of the most significant. Film studios will put out early releases to small audiences in a bid to get feedback and criticism to give an indication if the film is on the right track, or if they have a potential flop on their hands. This is valuable as it offers insights into the minds of the wider public, and if one particular element is hated by the majority, it can quickly be cut or re-edited, thus saving the studio time and money and also crafting a potentially more successful film.

https://screenrant.com/great-movies-test-audiences-not-like-list/