Op 2-9-2020 om 12:38 schreef Richard O'Keefe:

There is simply no point in "taking the first nine numbers out".

And there shouldn't BE a test for the string being empty, anywhere.

'' '-' '---' and so on should all be handled the same way.

Oh well, what stops you doing

���� digits := aString select: [:each | each ~= $-].

���� digits size = 10 ifFalse: [^false].

���� lastDigit := digits la ost.

���� digits := digits copyFrom: 1 to: 9.

���� ( (lastDigit = $X or: [lastDigit isDigit]) and: [

�������� digits allSatisfy: #isDigit]

���� ) ifFalse: [^false].

Now my code does not do this, but it is just 16 lines of code with

nothing that it would make sense to extract.

Nothing only that I could not think of this one for myself.
If I do it the TDD way I come more on the way Im currently thinking

but does this case then be covered

test14_EmptyIsbn
������ | result |
������ result := isbnVerifierCalculator isValidIsbn: ''.
������ self assert: result equals: false

and still I have to do the calcualation to see if it's valid.
If I understand the code well I can use the digits variable ?


Roelof