I’m trying to rerun a few Xamarin UITest that I created a few months ago in Visual Studio 2017 on Android. As expected, they all failed, but not because of the test is outdated, but the tool is broken.

First thing I discovered that the test finished immediately once it started.

========= Run test finished: 0 run (0:00:00.5110016) ==========

After some search online, new version of Visual Studio messed the test tool by adding something new. To revert the changes that affect this, go to Tools > Options > Test > General > Active Solution then uncheck “For improved performance, only use test adapters in test assembly folder or as specified in runsettings file.

I have no idea why, but this solution is provide here: https://forums.xamarin.com/discussion/140234/what-causes-ui-tests-to-run-without-getting-a-pass-or-fail

You should also turn change the logging level to diagnostic because you properly need that later.

Everything should be smoonth now, but the test failed immediately with the following information (not error).

The running adb server is incompatible with the Android SDK version in use by UITest

Instead of messing with the platform-tools folder by downgrading adb version suggested by many. The actual solution is pretty simple, open the Android SDK, and delete any folder with platform-tools.oldXXXXXXXX (those X are number).

Source: https://stackoverflow.com/questions/52254881/cannot-run-xamarin-ui-test-on-xamarin-forms-error-system-exception

While switching back to Visual Studio Mac try to run the UITest on iOS simulator, I hitted with another problem. The iOS emulator failed to launch and no output is given. In turn out the old Xamarin.UITest version 2.2.6 I used is not compatible with XCode 10, by upgrading it to version 2.2.7. It run smooth again.

Gosh, so many trouble.