before the default=novalue=? dbkey was the only available option
therefor the tests asserted:
`parameter 'my_name': an invalid option ('42') was selected (valid options: ?)`
with the current behavior the no_value value is not added to the
options. hence the test needs to assert:
`parameter 'my_name': requires a value, but no legal values defined`
M Bernt
b933e46fd7