r := NewDummyDataGen(100, 0)
	r.Seek(int64(len(alphabets)), 0)
	checkEq(readAll(r), readAll(NewDummyDataGen(100-int64(len(alphabets)), 0)))
}

// Compares all the bytes returned by the given readers. Any Read
// errors cause a `false` result. A string describing the error is
// also returned.
func cmpReaders(r1, r2 io.Reader) (bool, string) {
	bufLen := 32 * 1024