我想测试一个函数，并且希望这个测试失败。在使用cabal init启动项目后，我在app目录下的Main.hs文件中创建了findOddInt函数：

module Main where

findOddInt :: [Int] -> Int
findOddInt (x:xs) = undefined

main :: IO ()
main = putStrLn "Hello, Haskell!"

我创建了一个名为tests的目录，并创建了FindOddInt.hs文件：

module FindOddInt ( main ) where
import Main hiding ( main )
import Test.HUnit
import qualified System.Exit as Exit

test1 :: Test
test1 = TestCase (assertEqual "should return an odd integer" 3 (findOddInt [0, 1, 0, 1, 0]))

tests :: Test
tests = TestList [TestLabel "test1" test1]

main :: IO ()
main = do
    result <- runTestTT tests
    if failures result > 0 then Exit.exitFailure else Exit.exitSuccess

我的.cabal文件如下：

cabal-version:      2.4
name:               find-odd-int
version:            0.1.0.0

-- A short (one-line) description of the package.
-- synopsis:

-- A longer description of the package.
-- description:

-- A URL where users can report bugs.
-- bug-reports:

-- The license under which the package is released.
-- license:
author:             André Ferreira
maintainer:         andresouzafe@gmail.com

-- A copyright notice.
-- copyright:
-- category:
extra-source-files: CHANGELOG.md

executable find-odd-int
    main-is:          Main.hs

    -- Modules included in this executable, other than Main.
    -- other-modules:

    -- LANGUAGE extensions used by modules in this package.
    -- other-extensions:
    build-depends:    base ^>=4.14.3.0
    hs-source-dirs:   app
    default-language: Haskell2010

test-suite tests
    type: exitcode-stdio-1.0
    main-is: FindOddIntTest.hs
    build-depends: base ^>=4.14, HUnit ^>=1.6
    hs-source-dirs: app, tests
    other-modules: Main
    default-language: Haskell2010

设置好后，我运行cabal configure --enable-tests && cabal test并得到输出：

Build profile: -w ghc-8.10.7 -O1
In order, the following will be built (use -v for more details):
 - find-odd-int-0.1.0.0 (test:tests) (file app/Main.hs changed)
Preprocessing test suite 'tests' for find-odd-int-0.1.0.0..
Building test suite 'tests' for find-odd-int-0.1.0.0..
[1 of 2] Compiling Main             ( app/Main.hs, /home/asf/Projects/codewars-exercises/haskell/6-kyu/find-odd-int/dist-newstyle/build/x86_64-linux/ghc-8.10.7/find-odd-int-0.1.0.0/t/tests/build/tests/tests-tmp/Main.o )
[2 of 2] Compiling FindOddInt       ( tests/FindOddIntTest.hs, /home/asf/Projects/codewars-exercises/haskell/6-kyu/find-odd-int/dist-newstyle/build/x86_64-linux/ghc-8.10.7/find-odd-int-0.1.0.0/t/tests/build/tests/tests-tmp/FindOddInt.o ) [Main changed]
Linking /home/asf/Projects/codewars-exercises/haskell/6-kyu/find-odd-int/dist-newstyle/build/x86_64-linux/ghc-8.10.7/find-odd-int-0.1.0.0/t/tests/build/tests/tests ...
Running 1 test suites...
Test suite tests: RUNNING...
Test suite tests: PASS
Test suite logged to:
/home/asf/Projects/codewars-exercises/haskell/6-kyu/find-odd-int/dist-newstyle/build/x86_64-linux/ghc-8.10.7/find-odd-int-0.1.0.0/t/tests/test/find-odd-int-0.1.0.0-tests.log
1 of 1 test suites (1 of 1 test cases) passed.

我已经看了下面的帖子：

• Running “cabal test” passes although there are test failures
• Create and run a minimal test suite in Haskell using Hunit only

这些帖子不包括我的情况。任何帮助都是感激的。