It's not telling you what it's doing which is unfair. It does this:

a = add(1)(2)
b = add(3)(4)
test.assert_equals(add(1), 1, "A single call should return the number passed in")
test.assert_equals(a(3), 6, "Must be able to store curried functions")
test.expect(a == 3 and b == 7, "Must be able to store values")