private List<string> CheckNonCdnBundle(string bundleName, IEnumerable<string> allBundleDebugLines)
        {
            var errors = new List<string>();
            var allFilesWithDate = _searcher.UnpackBundle(allBundleDebugLines, s => errors.Add(s))
                .Select(x => new FileWithDateUpdated(_mvcAppPath, x)).ToList();

            if (!allFilesWithDate.Any())
            {
                errors.Add($"The bundle called {bundleName} did not contain any files to work on.");
                return errors;
            }

            var fileExtension = Path.GetExtension(allFilesWithDate.First().FileRelPath);
            var fileTypeInfo = _config.GetFileTypeData(fileExtension);

            AddErrorIfAnyFilesInBadFiles(bundleName,
                allFilesWithDate.Where(x => !x.Exists).Select(x => x.FileRelPath).ToList(), "were missing", errors);

            FileWithDateUpdated concatFileInfo = null;
            if (_checkForConcatFile)
            {
                concatFileInfo = new FileWithDateUpdated(_mvcAppPath,
                    Path.Combine(_mvcAppPath, fileTypeInfo.Directory, bundleName + fileExtension));
                if (!concatFileInfo.Exists)
                {
                    errors.Add($"Warning: the concat file for '{bundleName}' is missing. Continuing test.");
                    concatFileInfo = null;
                }
            }
            var minfiedFileInfo =
                new FileWithDateUpdated(_mvcAppPath,
                    Path.Combine(_mvcAppPath, fileTypeInfo.Directory, bundleName + ".min" + fileExtension));
            if (!minfiedFileInfo.Exists)
            {
                errors.Add($"The minified file for '{bundleName}' is missing.");
                return errors;
            }

            var newerFiles =
                allFilesWithDate.Where(x => x.LastWrittenUtc > (concatFileInfo ?? minfiedFileInfo).LastWrittenUtc)
                    .Select(x => x.FileRelPath).ToList();
            if (newerFiles.Any())
            {
                var concatOrMinfied = concatFileInfo == null ? "minified" : "concat";
                errors.Add(
                    $"The {concatOrMinfied} file for '{bundleName}' is out of date. Newer files are:\n - {string.Join("\n - ", newerFiles)}");

            }

            if (_checkForConcatFile && concatFileInfo != null && minfiedFileInfo.LastWrittenUtc < concatFileInfo.LastWrittenUtc)
                errors.Add($"The concat file for '{bundleName}' is newer than the minified file.");

            return errors;
        }
        /// <summary>
        /// This checks that the minified files for each bundle is older than the 
        /// BowerBundles.json file that defines what is in a bundle.
        /// </summary>
        /// <returns></returns>
        public string CheckBundleFileIsNotNewerThanMinifiedFiles()
        {
            var errors = new List<string>();

            var bundleInfo = new FileWithDateUpdated(_mvcAppPath, _bundleFilePath);

            //Note: we exclude the cdn bundles as the minified file is not normally created by the build process
            var badFiles = (from bundleName in _reader.BundleNames.Where(x => !_reader.GetBundleCdnInfo(x).Any())
                let fileExtension = Path.GetExtension(_reader.GetBundleDebugFiles(bundleName, "", s => errors.Add(s)).First())
                let fileTypeInfo = _config.GetFileTypeData(fileExtension)
                let minfiedFile = new FileWithDateUpdated(_mvcAppPath, Path.Combine(fileTypeInfo.Directory,
                        bundleName + ".min" + fileExtension))
                where !minfiedFile.Exists || minfiedFile.LastWrittenUtc < bundleInfo.LastWrittenUtc
                select minfiedFile.FileRelPath).ToList();

            if (errors.Any())
                return $"Errors in the BowerBundles file: {string.Join("\n", errors)}.";

            return badFiles.Any()
                ? $"The following minified files have not been updated since the change in the bundle file:\n - {string.Join("\n - ", badFiles)}"
                : null;
        }