oneM2M has published the oneM2M service layer core protocol (latest version of TS-004 is available here: WI-0009). In addition oneM2M has developed related documents Test Suite Structure and Test Purposes (TS-0018) and Abstract Test Suite Implementation eXtra Information for Test (TS-0019). You may retrieve the latest document around oneM2M conformance testing here: WI-0032.
TS-0019 presents the TTCN-3 conformance test suite. You may access the TTCN-3 code also via GitHub.