anchor.diff:  
         doCheck = true;
   
  -      checkPhase = ''
  -        export GDAL_DRIVER_PATH="$(pwd)"
  -        gdalinfo --formats | grep Haskell
  -
  -        export NIX_GHC="${ghc}/bin/ghc"
  -        export NIX_GHCPKG="${ghc}/bin/ghc-pkg"
  -        export NIX_GHC_DOCDIR="${ghc}/share/doc/ghc/html"
  -        export NIX_GHC_LIBDIR="${ghc}/lib/ghc-${ghc.version}"
  -
  -        cp ${testProgram} TestDataset.hs
  -        export GDAL_PLUGIN_HS_UNSAFE=YES
  -        echo $GDAL_DRIVER_PATH
  -        output=$(gdalinfo -stats HS:TestDataset)
  -        echo $output | grep -q "WGS_1984"
  -        echo $output | grep -q "NoData Value=5"
  -        echo $output \
  -          | grep -q "Minimum=42.000, Maximum=42.000, Mean=42.000, StdDev=0.000"
  -        '';
  +      checkPhase = testScript;
   
         shellHook = ''
           export GDAL_DRIVER_PATH="$(pwd):$GDAL_DRIVER_PATH"
  
positive.code: 
            dataset :: HSDatasetFactory
            dataset _ = return HSDataset
              { rasterSize   = 2560 :+: 1280
              , bands        = rasterBands
              , srs          = Just epsg4326
              , geotransform = Geotransform 0 0.001 0 0 0 0.001
  
negative.code:             pkgs.bindings-gdal
              ] ++ extraPackages pkgs);
  
          testScript = ''
            export GDAL_DRIVER_PATH="$(pwd)"
            gdalinfo --formats | grep Haskell
  
            export NIX_GHC="${ghc}/bin/ghc"
            export NIX_GHCPKG="${ghc}/bin/ghc-pkg"
            export NIX_GHC_DOCDIR="${ghc}/share/doc/ghc/html"
            export NIX_GHC_LIBDIR="${ghc}/lib/ghc-${ghc.version}"
  
            cp ${testDataset} TestDataset.hs
            export GDAL_PLUGIN_HS_UNSAFE=YES
            echo $GDAL_DRIVER_PATH
            output="$(gdalinfo -stats HS:TestDataset)"
            echo $output
            echo $output | grep -q "Size is 2550, 1270"
            echo $output | grep -q "Block=128x256"
            echo $output | grep -q "Type=Float32"
            echo $output | grep -q "WGS_1984"
            echo $output | grep -q "NoData Value=5"
            echo $output \
              | grep -q "Minimum=42.000, Maximum=42.000, Mean=42.000, StdDev=0.000"
            '';
  
          testDataset = builtins.toFile "TestDataset.hs" ''
            module TestDataset where
            import GDAL
            import OSR ( srsFromEPSG )
  