Confused about VC-API divergence

[lemoustachiste]

Hi,

I'm setting up those tests against my services.

I was getting some errors on the 1.03-conformance test so I investigated and it looks like while it calls my issue endpoint, the test suite does not conform or expect I don't know to the VC-API shape of response.

Here is the response data I get from the server, as I believe should be expected:

{
  "verifiableCredential": {
    "@context": [
      "https://www.w3.org/ns/credentials/v2",
      {
        "@vocab": "http://fallback.org/"
      },
      "https://w3id.org/security/data-integrity/v2"
    ],
    "credentialSubject": {
      "id": "did:example:subject"
    },
    "issuer": "did:myMethod:implementation:issuer:id",
    "proof": {
      "created": "2025-07-23T13:29:47Z",
      "cryptosuite": "merkle-proof-2019",
      "id": "urn:uuid:9f0262c1-00a5-4008-9058-47b7f28cf919",
      "proofPurpose": "assertionMethod",
      "proofValue": "zEuZQLZTYrdsDv2FAzRaHKm6AnkqB8NCg2hJnzNackPLMn1xCrb8X4n3GTeJt5jZnqGGnTh7fNonvtKF25YYs1RMP4Ckjzx3yeN1wtXiKv5mh7TycizX7W6SuZNzokmtddRnUjtg53cmfKzfktA4Byr4R5YdXHsSVCXi7oDKcraxTXnfGjL4LJPuQQ7xpQvG69TEq5A4WNnt3DUhPoQ1pxV1tZge13TiFxVDtMW4Dxqk8qE4KK5CET4GDVuyfijaWc6x4V8h9GNK2E3e1Jd6AsGibNeG1eo5WC7W4jKJMXyvyMA",
      "type": "DataIntegrityProof",
      "verificationMethod": "did:tdw:Qmcox8WT7JK9zaWWcmVFyQE3npmxSzHsB54GZjFp5uFBRn:blockcerts.org#oGpk97CR"
    },
    "type": [
      "VerifiableCredential"
    ]
  }
}

I have to modify the test file to:

const response = await endpoints.issue(require( './input/credential-ok.json'));
issuedVc = response.verifiableCredential;

For the tests to pass, showing that it does not understand the VC-API response, but the README says it should? https://github.com/w3c/vc-data-model-2.0-test-suite?tab=readme-ov-file#implementation

I'm confused as to what's wrong in this case?

EDIT: updated response object by the one returned by the server

[dlongley]

The linked test file looks wrong -- that it should be obtaining the VC from the verifiableCredential property. @lemoustachiste, I think your code is right, the README is right, and the test suite code has a bug (probably from a much older revision).

We probably need to modify this to accept both for now and transition to only accepting the proper response in the future. cc: @BigBlueHat

[lemoustachiste]

Thanks for your answer @dlongley, to be noted that potentially other test files are effected, and I have for now changed the fix to the response of issue, although I suppose there could be a façade between the 2.

[BigBlueHat]

@dlongley I think the issue here is that VC API has changed over the last several years.

There will be ongoing tension (consequently) with shift in the VC API and what the (much slower moving) test suites will/should support.

This is core to why we now refer to the API in these suites as the "test suite API based on VC API" https://github.com/w3c/vc-data-model-2.0-test-suite?tab=readme-ov-file#test-suite-http-api

We have others interested in adding OID4VC/VP support also, but if we go the route of supporting other protocols (besides the current "test suite API" one) then we'll need abstractions of Endpoint.js to handle the juggling rather than changing each test suite to support all the various in and outbound wrappers.

The test suites themselves should only care about the actual VC object--not the disposable wrappers used by any API.

Make sense? 😃 Happy to hear counter point.