Hi,

• remove the input validation. There are already enough edge cases like that and it's just another layer of annoying things to handle (moreover, the name of the test is wrong: "non numeric values...", while you have inputs with Infinity or the string version of this that should work too)
• don't ever use test.expect. Or provide the actual output too in the error message. => just use assert.equal (using chai)
• don't begin the full test suite with the random tests. Put the sample tests and all the fixed tests there first.
• expected: 1011011 --> "one million eleven thousand and eleven". My output: "one million and eleven thousand and eleven" because of the description:

Use the word 'and' to separate the tens space from the hundreds space in each period (grouping of 3 or less numbers)

but this is in contradiction with:

the word 'and' for numbers over 1000 is used to separate the tens and ones space from the lowest number

=> don't split the infos like that, you're just annoying the users. For instance

More generally, provide the complete (clear) set of rules, then provide some examples. So that the rules are visible in some lines, and not spreaded on a complete screen.

Hi,

Too close to this and other related katas. Please unpublish it (you should look for preexisting katas before authoring something ;) )

edit: "fun" fact: you already solved that one... x/