Whenever I run my projects JUnit test (using JUnit 5 with Java 9 and Eclipse Oxygen 1.a) I encounter the problem that eclipse can\'t find any tests.
I am using eclipse 2019-09.
I had to update the junit-bom version to at least 5.4.0. I previously had 5.3.1 and that caused the same symptoms of the OP.
My config is now:
org.junit junit-bom 5.5.2 pom import