So many tests! :+1: 

How about one with an unterminated quote (Xcode handles this) ...

```
assertThat(ParseArgumentsFromArgumentString(@"Arg1 \"Arg 2"), equalTo(@[@"Arg1", @"Arg 2"]));
```

And, can you add some for single quotes, too?  Also, Xcode seems to allow for escaped single quotes inside of single quotes.