When sending /notifications/eventTypes/<non_exist_id> it is expected to return 404 not found error and not 200.

Example:

curl -XGET -i -u insights-qa:redhatqa https://qa.cloud.redhat.com/api/notifications/v1.0/notifications/eventTypes/999
HTTP/1.1 200 OK
X-Powered-By: Express
x-fakamai-env: qa
x-fakamai-app-hint: API
x-fakamai-downstream-host: https://api-gateway-qa.5a9f.insights-dev.openshiftapps.com
server: openresty/1.13.6.1
date: Tue, 10 Nov 2020 13:36:08 GMT
content-type: application/json
x-rh-insights-request-id: 2acaa07789b94753b22895b004739a19
x-content-type-options: nosniff
set-cookie: a549c90418df47840900855e57bbdfae=82325ac5afb310d09d6d4ae0010d80b4; path=/; HttpOnly; Secure
cache-control: private
connection: keep-alive
Transfer-Encoding: chunked