chore:  fix promise tests to break the build when they fail (#305)
chore:  fix promise tests to break the build when they fail (#305)

* squash: return the promise that is being tested

fixes #303 

Signed-off-by: Lucas Holmquist <53dd6492234f115cc187fc638efb40daab835454@redhat.com>

cloudevents/sdk-javascript,cloudevents/sdk-javascript