It can happen out of many reasons.
- Maybe the project is still loading, please give it some time to load.
Ctrl+Shift+Pand clean your java servers.
- Refresh/Reload .
- If It is still taking longer to appear, then it is because of Your internet connection .
There is a workaround if testcase needed to run, i.e.
The left pane option(The beaker option) to run tests for the time being.