Cabal output is redirected but not generated

问题

I have a fairly simple haskell project set up, where I just want to have the framework working with testing and so on before I actually start coding. I have my source files for an executable in a /src directory (where / is the project's root) and my tests in a /testsuite directory. /testsuite contains a simple test file called TestSuite.hs with main = Test.Framework.defautMain tests as the implementation of main. The problem is, when I run

cabal clean && cabal configure --enable-tests && cabal build

I get the warning

output was redirected with -o, but no output will be generated because there is no main module.

The build works fine when I don't specify --enable-tests. My cabal file is:

Name:                Example
Version:             0.1
Synopsis:            Synopsis
Description:
    Long description.
License:             GPL
License-File:        LICENSE
Author:              SeanK
Maintainer:          email@example.com
Category:            Development
Build-Type:          Simple
Cabal-Version:       >= 1.8

Test-Suite test
    Type:               exitcode-stdio-1.0
    Main-Is:            TestSuite.hs
    Build-Depends:      base >= 3 && < 5,
                        test-framework,
                        test-framework-quickcheck
                        -- QuickCheck
    Hs-Source-Dirs:     src,
                        testsuite

Executable example
    Main-Is:            Main.hs
    -- Other-Modules:       
    Build-Depends:      base >= 3 && < 5,
                        haskell98
    Hs-Source-Dirs:     src
    Ghc-Options:        -Wall

I have QuickCheck disabled because I'm not using (==>) at the moment, which is the only function I currently need from it. The rest should be straight-forward. Any help would be greatly appreciated.

回答1:

You should define module name in your TestSuite.hs file as Main, like there for example.

A quote from The Haskell 98 Report:

A Haskell program is a collection of modules, one of which, by convention, must be called Main and must export the value main.

回答2:

Instead of renaming the TestSuite module as Fedor suggests you could add a GHC option to set the name of the main module to your Cabal file:

Test-Suite testFedor
    ghc-options:    -main-is TestSuite

Apparently Cabal main-is and GHC main-is are different. I don't know how.

来源：https://stackoverflow.com/questions/12133320/cabal-output-is-redirected-but-not-generated

标签

testing

haskell

build

cabal