cc-switch-cli/internal/cli/tty.go

package cli

import (
	"io"
	"os"

	"golang.org/x/term"
)

// isTTY reports whether r is attached to a terminal. In production the app
// passes os.Stdin, which might be a tty. In tests a bytes.Buffer is supplied
// and the type assertion fails, so we correctly treat it as non-tty.
func isTTY(r io.Reader) bool {
	f, ok := r.(*os.File)
	if !ok {
		return false
	}
	return term.IsTerminal(int(f.Fd()))
}