From the description you can say that all parameters will be separated by space, and the testcase when they may not be separated by such is an extra one and not required for solution:

Each switch or parameter is separated by a space. (For an extra challenge read: It is not mandatory that each element is separated by a space.)

However, the actual testcases DO include that extra challenge, and due to the nature of test frameworks and Codewars itself, the kata can be completed if only all tests are passed. That means that extra challenge is actually mandatory for completing the kata, thus contraditing itself :/

Either explicitily make that requirement as required (then the difficulty should increase from 6-5 to 5-4) or exclude that case at all or insert it as sample test.