# DocTest

### From HaskellWiki

## Contents |

## 1 What is DocTest

DocTest is a small program, that checks examples in Haskell source code comments. It is modeled after doctest for Python.

## 2 Installation

DocTest is available from Hackage. Install it by typing (on your Unix shell):

$ cabal install doctest

## 3 Usage

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 -- | Compute Fibonacci numbers -- -- Examples: -- -- >>> fib 10 -- 55 -- -- >>> fib 5 -- 5 fib :: Int -> Int 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.hsLines starting with

*expressions*.

All comment lines following an expression denote the
*result* of that expression. Result is defined by what an REPL

evaluating that expression.

## 4 Hacking

DocTest is still experimental. You can find a reference to the public source repository at Hackage.

Patches are gladly welcome!