Thanks.
According to this...
https://support.smartbear.com/readyapi/docs/testing/assertions/reference/compliance/swagger.html
... the assertion only works by looking at the content-type defined for the response, but yours specifies it at the API level rather than the response level.
That might be the problem. I couldn't say for sure. Since I don't have ReadyAPI, I would recommend again that you ask on the SoapUI Pro forum.
If it turns out that really is all the support that ReadyAPI has for OpenAPI, that seems pretty disappointing. Maybe there's another tool that's better suited for this specific type of test on your API. Aren't SmartBear supposed to be driving OpenAPI adoption? Anyway, I came across Dredd when I was looking online.
Thank you very much for your input.
