Trying to Write New Tests for a New Pandoc Writer

src.Text.Pandoc.Writers.TEI.hs

{-# LANGUAGE OverloadedStrings #-}
{-
Copyright (C) 2006-2015 John MacFarlane <jgm@berkeley.edu>

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-}

{- |
   Module      : Text.Pandoc.Writers.TEI
   Copyright   : Copyright (C) 2006-2015 John MacFarlane
   License     : GNU GPL, version 2 or above

   Maintainer  : John MacFarlane <jgm@berkeley.edu>
   Stability   : alpha
   Portability : portable

Conversion of a 'Pandoc' document to a string representation.

-}
module Text.Pandoc.Writers.TEI ( writeTEI ) where
import Text.Pandoc.Options ( WriterOptions(..), WrapOption(..) )
import Data.List ( intersperse )
import Text.Pandoc.Definition
import Text.Pandoc.Pretty

writeTEI :: WriterOptions -> Pandoc -> String
writeTEI opts document =
  "empty"

test-pandoc.hs

{-# OPTIONS_GHC -Wall #-}

module Main where

import Test.Framework
import GHC.IO.Encoding
import qualified Tests.Old
import qualified Tests.Readers.LaTeX
import qualified Tests.Readers.Markdown
import qualified Tests.Readers.Org
import qualified Tests.Readers.HTML
import qualified Tests.Readers.RST
import qualified Tests.Readers.Docx
import qualified Tests.Readers.Odt
import qualified Tests.Readers.Txt2Tags
import qualified Tests.Readers.EPUB
import qualified Tests.Writers.ConTeXt
import qualified Tests.Writers.LaTeX
import qualified Tests.Writers.HTML
import qualified Tests.Writers.Docbook
import qualified Tests.Writers.Native
import qualified Tests.Writers.Markdown
import qualified Tests.Writers.Plain
import qualified Tests.Writers.AsciiDoc
import qualified Tests.Writers.Docx
import qualified Tests.Writers.RST
import qualified Tests.Writers.TEI
import qualified Tests.Shared
import qualified Tests.Walk
import Text.Pandoc.Shared (inDirectory)
import System.Environment (getArgs)

tests :: [Test]
tests = [ testGroup "Old" Tests.Old.tests
        , testGroup "Shared" Tests.Shared.tests
        , testGroup "Walk" Tests.Walk.tests
        , testGroup "Writers"
          [ testGroup "Native" Tests.Writers.Native.tests
          , testGroup "ConTeXt" Tests.Writers.ConTeXt.tests
          , testGroup "LaTeX" Tests.Writers.LaTeX.tests
          , testGroup "HTML" Tests.Writers.HTML.tests
          , testGroup "Docbook" Tests.Writers.Docbook.tests
          , testGroup "Markdown" Tests.Writers.Markdown.tests
          , testGroup "Plain" Tests.Writers.Plain.tests
          , testGroup "AsciiDoc" Tests.Writers.AsciiDoc.tests
          , testGroup "Docx" Tests.Writers.Docx.tests
          , testGroup "RST" Tests.Writers.RST.tests
          , testGroup "TEI" Tests.Writers.TEI.tests
          ]
        , testGroup "Readers"
          [ testGroup "LaTeX" Tests.Readers.LaTeX.tests
          , testGroup "Markdown" Tests.Readers.Markdown.tests
          , testGroup "HTML" Tests.Readers.HTML.tests
          , testGroup "Org" Tests.Readers.Org.tests
          , testGroup "RST" Tests.Readers.RST.tests
          , testGroup "Docx" Tests.Readers.Docx.tests
          , testGroup "Odt" Tests.Readers.Odt.tests
          , testGroup "Txt2Tags" Tests.Readers.Txt2Tags.tests
          , testGroup "EPUB" Tests.Readers.EPUB.tests
          ]
        ]

main :: IO ()
main = do
  setLocaleEncoding utf8
  args <- getArgs
  inDirectory "tests" $ defaultMainWithArgs tests args

tests.Tests.Writers.TEI.hs

{-# LANGUAGE OverloadedStrings #-}
module Tests.Writers.TEI (tests) where

import Test.Framework
import Text.Pandoc.Builder
import Text.Pandoc
import Tests.Helpers
import Tests.Arbitrary()

{-
  "my test" =: X =?> Y

is shorthand for

  test html "my test" $ X =?> Y

which is in turn shorthand for

  test html "my test" (X,Y)
-}

infix 4 =:
(=:) :: (ToString a, ToPandoc a)
     => String -> (a, String) -> Test
(=:) = test (writeTEI def . toPandoc)

tests :: [Test]
tests = [ testGroup "block elements"
          ["para"          =: para "Lorem ipsum cetera."
                           =?> "<p>Lorem ipsum cetera.</p>" 
          ]
        ]

You are not importing Text.Pandoc.Writers.TEI in Tests.Pandoc.TEI. However, you probably also need to add Text.Pandoc.Writers.TEI to the .cabal fie for it to work as well.