A production studio played a movie for a test audience and watched their reactioms

A test screening is a preview screening of a movie or television show before its general release in order to gauge audience reaction. Preview audiences are selected from a cross-section of the population, and are usually asked to complete a questionnaire or provide feedback in some form. Harold Lloyd is credited with inventing the concept, having used it as early as 1928.[1] Test screenings have been recommended even for starting filmmakers "even if a film festival is fast approaching".