replaced ISO 8601 test with regular expression

[tzemanovic]

Hi,

I've recently finished a backend impl (#202), but had trouble with the postman test, because SQLite I've used for the project uses 3 more decimals for microseconds, which get lost in the new Date(t).toISOString() conversion and fail the tests, even though it's a valid ISO 8601 date format.

I've adapted the regex from https://stackoverflow.com/a/3143231/3210255.

I also tried to set the regex as a variable in the collection with:

{
  "variable": [
    {
      "name": "iso8601",
      "value": "/^\\d{4,}-[01]\\d-[0-3]\\dT[0-2]\\d:[0-5]\\d:[0-5]\\d\\.\\d+(?:[+-][0-2]\\d:[0-5]\\d|Z)$/",
      "type": "RegExp"
    }
  ], ...
}

and using it in the tests with:

ps.variables.get('iso8601')

to avoid repetition, but I couldn't get it to work in newman (with latest version 4.1.0), only in postman, so I left it out.

[schnef]

There is a problem in the regex for timestamps with a "Z" at the end. The regex currently is: /^\\d{4,}-[01]\\d-[0-3]\\dT[0-2]\\d:[0-5]\\d:[0-5]\\d\\.\\d+(?:[+-][0-2]\\d:[0-5]\\d|Z)$/ but should be:
/^\\d{4,}-[01]\\d-[0-3]\\dT[0-2]\\d:[0-5]\\d:[0-5]\\d\\.\\d+(?:[+-][0-2]\\d:[0-5]\\d)|Z$/, i.e. the last `)' currently is at the wrong position.