getHeaderLen :: FilePath -> IO Int
getHeaderLen file = do
    bs <- BL.readFile file
    let Just tc = decode bs :: Maybe Test
    let len = length $ cases tc
    return len
getHeaderLen :: FilePath -> IO Int
getHeaderLen file = do
    bs <- BL.readFile file
    let Just tc = decode bs :: Maybe Test
    let len = length $ cases tc
    return len
getHeaderLen file = do
    bs <- BL.readFile file
    let Just tc = decode bs :: Maybe Test
    let len = length $ cases tc
    return len