The FHIRPath specification allows timezone offset behavior to be determined by policy:

https://build.fhir.org/ig/HL7/FHIRPath/#datetime-equality

This makes a single set of tests to determine correct behavior dependent on policy decisions. To address this, propose adding two sets of tests:

1. Tests that validate correct timezoneoffset behavior if the policy decision is not to provide a timezone offset (for values that do not have one)
2. Tests that validate correct timezone offset behavior if the policy decision is to default to the timezone offset of the server.