Also happening in Xcode 13.1 running in iOS 15.0 simulators, 20% of our tests failed because of this, reported in FB9794773
Looking at the xcresult logs I found this info but not too helpful:
18:02:04.554 Xcode[72384:6322690] 8D4BD7E8-6674-461B-9079-C12C459B0530: Launching app with identifier: com.some.identifier and options: {
.... // OMITED BECAUSE IT'S TOO LARGE
}
18:02:04.723 Xcode[72384:6322689] 8D4BD7E8-6674-461B-9079-C12C459B0530: Launched app with identifier: com.some.identifier (pid = 80902)
18:02:04.724 Xcode[72384:6322689] 📱<DVTiPhoneSimulator (0x14be19470), iPhone 8 Plus, unknown class, 15.0 (19A339), 8D4BD7E8-6674-461B-9079-C12C459B0530> tracking pid 80902
18:02:04.724 Xcode[72384:6322689] 📱<DVTiPhoneSimulator (0x14be19470), iPhone 8 Plus, unknown class, 15.0 (19A339), 8D4BD7E8-6674-461B-9079-C12C459B0530> checking to see if pid 80902 is valid: kill(pid, 0) = 0 (YES, it's still running)
18:02:04.732 Xcode[72384:5738902] Test process runnable PID is 80902.
18:02:04.732 Xcode[72384:6322621] XCTHTestOperationStateMachine: Transitioning from state Initial to AcquiredPID
18:07:34.729 Xcode[72384:6327051] XCTHTestOperationStateMachine: Startup timer fired; the test runner has not made forward progress for 300.00 seconds
18:07:34.730 Xcode[72384:6327051] XCTHTestOperationStateMachine: Transitioning from state AcquiredPID to BootstrappingHang
18:07:34.730 Xcode[72384:5738902] Acquiring spindump to help determine why test runner got stuck after launching
18:07:39.927 Xcode[72384:5738902] Retrieved spindump data of 3394 bytes
18:07:39.927 Xcode[72384:5738902] Test operation failure: Test runner never began executing tests after launching
18:07:39.934 Xcode[72384:5738902] _finishWithError:Error Domain=XCTHTestOperationCoordinatorErrorDomain Code=14 "Test runner never began executing tests after launching" UserInfo={NSLocalizedDescription=Test runner never began executing tests after launching}
Maybe there is a way to increment the startup timeout (300s) from Test Runner?