What is DocTest
DocTest is a small program, that checks examples in Haskell source code comments. It is modeled after doctest for Python.
Bellow is a small Haskell module. The module contains source code comments. Those comments are examples from an interactive Haskell session and demonstrate how the module is used.
module Fib where -- Examples: -- -- > fib 10 -- 55 -- > fib 5 -- 5 fib 0 = 0 fib 1 = 1 fib n = fib (n - 1) + fib (n - 2)
With DocTest you may checks if the implementation satisfies the given examples, by typing (on your Unix shell):
$ doctest Fib.hs
Lines starting with
-- > denote expressions.
All comment lines following an expression denote the
result of that expression. Result is defined by what an REPL
(e.g. ghci) prints to
evaluating that expression.