Adding tests for the ordinal filter

Ready for Review

> Add tests for the ordinal filter
Similar to the 'describing the behavior in the `it` message' comment I left above, I'd make a seperate `it` for a negative number, and for null too.  And then move the 0 => 0th case down here as its a similar edge case.

1e2 and 2^40 get converted to `100` and `42` before they are passed in to our function, so they don't need to be test cases as they are more testing edge cases in the JS language :]