(check-expect expr expr)
A test case to check that the first expr produces the same value as the second expr, where the latter is normally an immediate value.
(check-within expr expr expr)
Like check-expect, but with an extra expression that produces a number delta. The test case checks that each number in the result of the first expr is within delta of each corresponding number from the second expr.
(check-error expr expr)
A test case to check that the first expr signals an error, where the error messages matches the string produced by the second expr.