@Override
        public List<ApplicationFile> listFiles(PathFilter filter) {
            if ( ! isDirectory()) return List.of();
            return Arrays.stream(file.listFiles()).filter(f -> filter.accept(Path.fromString(f.toString())))
                         .map(f -> new MockApplicationFile(asApplicationRelativePath(f), root))
                         .collect(Collectors.toList());
        }
The content of this file, or null to read it from the file system.
config-model/src/main/java/com/yahoo/config/model/test/MockApplicationPackage.java