; positive assert
(assert t)
(assert ())
(assert 1)

; not
(assert (not nil))
(assert (not nil))
(assert (not (not t)))

; or
(assert (not (or nil nil)))
(assert (or 1 nil))
(assert (or nil 1))
(assert (or 1 1))

; and
(assert (not (and nil nil)))
(assert (not (and 1 nil)))
(assert (not (and 1 nil)))
(assert (and 1 1))

; xor
(assert (not (xor nil nil)))
(assert (xor nil 1))
(assert (xor 1 nil))
(assert (not (xor 1 1)))