expect is used to run a bunch of interactive tests for the fish shell (https://github.com/fish-shell/fish-shell/tree/master/tests https://github.com/fish-shell/

expect is used to run a bunch of interactive tests for the fish shell (https://github.com/fish-shell/fish-shell/tree/master/tests https://github.com/fish-shell/fish-shell/tree/master/tests, all of the files ending in .expect, where the file interactive.expect.rc defines a bunch of utilities).