astropy
Handle UWS XML quote negative values
Currently, negative quote values do not work.
UWS 1.1 specifies 'nil' value should be used for an unspecified quote value, but UWS 1.0 allows negative numbers too:
UWS 1.1 (http://www.ivoa.net/documents/UWS/20161024/REC-UWS-1.1-20161024.html#Quote)
Quoting for a computational job is notoriously difficult. A UWS implementation should provide a quote object, in order that the two-phase committal of jobs be uniform across all UWS, but it may supply a “don't know” answer for the completion time, indicated by an XML xsi:nil element in an XML representation of the quote object.
UWS 1.0 (http://www.ivoa.net/documents/UWS/20101010/REC-UWS-1.0-20101010.html#Quote)
Quoting for a computational job is notoriously difficult. A UWS implementation must always provide a quote object, in order that the two-phase committal of jobs be uniform across all UWS, but it may supply a “don't know” answer for the completion time, indicated by a negative value or an XML nil element in an XML representation of the quote object.
I think that, in order to ensure UWS compatibility, negative numbers should be allowed.
