This code system http://hl7.org/fhir/testscript-scope-conformance-codes defines the following codes:

CodeDisplayDefinition
required RequiredAll tests are expected to pass. Warning statuses are permitted. This is the default value.
optional OptionalAll tests are expected to pass but non-pass statuses may be allowed.
strict StrictAll tests are expected to pass. Warnings are treated as a failure.
<status value="active"/><experimental value="false"/><date value="2021-01-25T17:01:24-04:00"/><publisher value="HL7 (FHIR Project)"/><contact><telecom><system value="url"/><value value="http://hl7.org/fhir"/></telecom><telecom><system value="email"/><value value="fhir@lists.hl7.org"/></telecom></contact><description value="The expectation of whether the test must pass for the system to be considered conformant with the artifact."/><jurisdiction><coding><system value="http://unstats.un.org/unsd/methods/m49/m49.htm"/><code value="001"/><display value="World"/></coding></jurisdiction><caseSensitive value="true"/><valueSet value="http://hl7.org/fhir/ValueSet/testscript-scope-conformance-codes"/><content value="complete"/><concept><code value="required"/><display value="Required"/><definition value="All tests are expected to pass. Warning statuses are permitted. This is the default value."/></concept><concept><code value="optional"/><display value="Optional"/><definition value="All tests are expected to pass but non-pass statuses may be allowed."/></concept><concept><code value="strict"/><display value="Strict"/><definition value="All tests are expected to pass. Warnings are treated as a failure."/></concept></CodeSystem>