       targetFiles.forEach (file) ->
         promises.push q.nfcall(
           fs.readFile,
-          path.join("./tests/data/multiple", file)
+          path.join("./tests/data/multiple", file),
+          "utf-8"
         ).then(
           (data) ->
             resultPath = path.join("./tests/results/multiple", file)

      targetPromises = [
        q.nfcall(
          fs.readFile,
          "./tests/data/single/source.css"
        ).then(
          (css) -> right.file = removeMapFile(css.toString "utf-8").trim()
        )
        q.nfcall(
          fs.readFile,
          "./tests/data/single/source.css.map"
        ).then(
          (map) ->
            right.sourcemap = JSON.parse(map)

            )
            promises.push q.nfcall(
              fs.readFile,
              resultPath + ".map",
              "utf-8"
            ).then(
              (map) ->
                sourcemap = JSON.parse map
