Tests.hs

{-# LANGUAGE OverloadedStrings #-}
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module Hakyll.Images.Metadata.Tests
    ( tests
    ) where


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import           Test.Tasty             (TestTree, testGroup)
import           Test.Tasty.HUnit       (Assertion, assertBool, testCase)


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import qualified Data.ByteString        as B
import           Data.Maybe             (fromMaybe)
import           Hakyll.Images
import           Hakyll.Images.Common

import qualified Hakyll.Images.Metadata as M

import           Text.Printf            (printf)

fromAssertions :: String       -- ^ Name
               -> [Assertion]  -- ^ Cases
               -> [TestTree]   -- ^ Result tests
fromAssertions name =
    zipWith testCase [printf "[%2d] %s" n name | n <- [1 :: Int ..]]

testJpg :: IO Image 
testJpg = Image Jpeg <$> (B.readFile "tests/data/piccolo.jpg")

testMetadata :: Assertion
testMetadata = do
    im <- testJpg
    let meta = metadata im
        height = fromMaybe 0 (M.lookup M.Height meta)
        width  = fromMaybe 0 (M.lookup M.Width meta)
    
    -- The following values of (width, height) = (1170, 647) are 
    -- specific to the "piccolo.jpg" image
    assertBool "Metadata was not decoded properly" (height == 647)
    assertBool "Metadata was not decoded properly" (width == 1170)

tests :: TestTree
tests = testGroup "Hakyll.Images.Metadata.Tests" $ concat
   [ fromAssertions "metadata" [ testMetadata ]
   ]