public static FileAcquirer returnFiles(Map<String, File> files) {
        return new MockFileAcquirer() {
            @Override
            public File waitFor(FileReference fileReference, long timeout, TimeUnit timeUnit) {
                return files.get(fileReference.value());
            }
        };
    }
Creates a FileAcquirer that maps from fileReference.value to a file. *
fileacquirer/src/main/java/com/yahoo/filedistribution/fileacquirer/MockFileAcquirer.java