About this Kata

Alistair Cockburn wrote a blog post about this kata, in response to the Seb Rose kata proposition.

Problem Description

Given a letter, print a diamond starting with ‘A’ with the supplied letter at the widest point.

For example: print-diamond 'C' prints

  A
 B B
C   C
 B B
  A

Addition

In case of an invalid character an IllegalArgumentException should be thrown.