• Still no random tests (many fixed tests != random tests)

• assert.strictEqual should be used

• The "random tests" only generate a string format of \d\d\d-\d\d\d\d

• Description should be language-agnostic (no mention of function name)

• Example tests should be stated clearer by using code blocks

• duplicate and more

The log message is kinda misleading.

Push 3 items, ( add [86,51,67] to... )

From that message, people would thought the input is an array (e.g. array.push([86,51,67])). But in reality, it can also mean separate arguments (e.g. array.push(86,51,67).
I'd suggest changing the brackets to parentheses or none at all.

Also, you might want to remind people in the description that the function should accept multiple arguments.

If this.length does not exist, it will be created with an initial value of 0. This does not seem to be tested. (Will have to .call or .apply to use a this that isn't an Array. But .push can work on other Objects.)

CoffeeScript translation Kumited! Please Accept :D