EAN-13 exercies

Read about EAN 13 on wikipedia.

Implement se.vbgt.ean13.EAN13 so it passes the tests below (and it will be a start for generating barcode images).

Modules, in text, will be represented with a bar | and absence of modules with a space .

EAN13NumberTest

• Must be 13 digits
• Must be correct check digit

EAN13GroupingTest

• Test of grouping of first part of modules

EAN13ModuleTest1

• Test encoding digit to modules, depending on group

EAN13ModuleTest2

• Testing length
• Testing markers
  • start
  • end
  • middle

EAN13ModuleTest3

• Test of actual complete modules of barcodes

Bonus

Actually generate a PNG image of the barcode, remember the quiet zone! (Barcodes are introverts)