Also we can use objects with condition in array.

There are no arrays in the spec. ( They may magically appear in the implementation, but that is solver's problem, not the specs'. )

And also we can mix different options in an array

Where is this array you keep speaking of ?!?

The empty string is a valid key in objects ( ask me how I know .. :P ).

There should be fixed tests with this edge case, as well as with other somewhat falsy values for keys ( keys are always Strings ) ( unless they're Symbols, but please continue just ignoring that ), so the best you can do, apart from "", are things like "0" and "false".

You should have chai.config.truncateThreshold=0 at the start of testing ( both Example and Submit ), for better failure messages.