I'm not quite sure why the random tests in ruby are expected to display values outside the middle of the string. Maybe I'm missing something. Can someone explain why expected values exclude the middle characters for random tests and not for primary tests?

Testing for bLXT
It should work for random inputs too - Expected: "bT", instead got: "LX"
Testing for hBRnHu
It should work for random inputs too - Expected: "BH", instead got: "Rn"
Testing for FSCfE
It should work for random inputs too - Expected: "Sf", instead got: "C"