I had the same issue in my project, which is still on Swift 5. The tests wouldn’t run even though the project built successfully. I tried converting the folder to a group and setting the Swift 6 compiler for the test target, but it didn’t help. I found a thread suggesting the problem could be with the simulator. The solution was to delete all simulators using xcrun simctl delete all. After that, the tests started running. I did run into some dependency issues, but that’s a separate problem. Try this solution, it might help you!