This actually works :)

```
1.9.3-p125 :001 > a = nil
 => nil 
1.9.3-p125 :002 > p(*a || :test)
:test
 => :test 
1.9.3-p125 :003 > a = [:a, :b]
 => [:a, :b] 
1.9.3-p125 :004 > p(*a || :test)
:a
:b
 => [:a, :b] 
```

In most of the tests, default store is actually set to nil so scenario is part of the test suite.