Use accessors (new, get, set) instead of direct field access

[gab-arrobo]

Also add a couple unit tests

[Copilot]

Pull request overview

This PR updates AMF code to prefer OpenAPI model constructors/accessors (New*, Get*, Set*) over direct struct-field access, and adds/updates unit tests to validate multipart payload handling and RAT type behavior.

Changes:

• Refactor multiple call sites to use OpenAPI model constructors and setter/getter methods instead of direct field mutation.
• Adjust UE context / event exposure logic to construct nested model objects via accessors.
• Add/extend unit tests for SM context creation multipart payloads and RAT type upgrade behavior.

Reviewed changes

Copilot reviewed 20 out of 20 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
producer/ue_context.go	Renames UE context procedures to unexported helpers and switches several model constructions to New*/Set*.
producer/event_exposure.go	Uses constructors/setters for event subscription responses and refactors expiry-duration calculation helper.
producer/callback/callback_test.go	Updates callback tests to use model constructors and decode into allocated structs.
ngap/message/send.go	Uses NewNgApCause(...) constructor.
ngap/message/send_test.go.test	Removes legacy test file.
ngap/message/build_test.go	Uses constructors/setters for subscription data setup in tests.
ngap/handler.go	Uses NewNgApCause(...) in multiple NGAP handlers.
nfregistration/nf_registration_test.go	Updates mocks to return NewNFProfileWithDefaults().
gmm/rat_type_integration_test.go	Adds an integration-style test validating RAT type upgrade from NGSetup RATInformation.
gmm/handler.go	Uses constructors/setters for N1/N2 payload references, AllowedNssai, and resynchronization info.
gmm/handler_test.go	Updates tests to use setters/constructors for location and S-NSSAI.
context/ran_ue.go	Uses setters for NR location nested fields and N3GA location fields.
context/amf_ue.go	Uses constructors for nested JSON data containers during UE marshaling.
consumer/ue_authentication.go	Uses NewPlmnIdNid(...) constructor.
consumer/sm_context.go	Refactors SM context create/update/release payload building to use setters; threads requestType into create request builder.
consumer/sm_context_test.go	Adds SM context create test verifying requestType + N1 multipart payload, plus multipart helper improvements.
consumer/nf_management.go	Uses constructors/setters for default notification subscription and returns default NFProfile on error paths.
consumer/communication.go	Uses NewN1MessageContainer(...) constructor for RegRequest.
consumer/communication_test.go	Uses NewN2InfoContent(...) in UE context transfer response test.
consumer/am_policy.go	Uses NewPlmnIdNid(...) for ServingPlmn.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.