I am getting the error "Test reports were found but none of them are new. Did tests run?" when trying to send unit test results by email. The reason is that I have a dedicated Jenkins job that imports the artifacts from a test job to itself, and sends the test results by email. The reason why I am doing this is because I don't want Jenkins to send all the developers email during the night :) so I am "post-poning" the email sending since Jenkins itself does not support delayed email notifications (sadly).
However, by the time the "send test results by email" job executes, the tests are hours old and I get the error as specified in the question title. Any ideas on how to get around this problem?
You could try updating the timestamps of the test reports as a build step ("Execute shell script"). E.g.
cd path/to/test/reports
touch *.xml