Testing
Since callbacks are simply invocations of the program they can be tested directly.
example _carapace bash example condition --required ''
valid
invalid
example _carapace elvish example condition --required ''
[{"Value":"valid","Display":"valid"},{"Value":"invalid","Display":"invalid"}]
example _carapace fish example condition --required ''
valid
invalid
example _carapace powershell example condition --required ''
[{"CompletionText":"valid","ListItemText":"valid","ToolTip":" "},{"CompletionText":"invalid","ListItemText":"invalid","ToolTip":" "}]
example _carapace xonsh example condition --required ''
[{"Value":"valid","Display":"valid","Description":""},{"Value":"invalid","Display":"invalid","Description":""}]
example _carapace zsh example condition --required ''
valid valid
invalid invalid