Flutter allows you to create UI tests with Flutter Deriver. By creating UI tests and automate UI test execution helps to identify most of the UI issues even before QA testing. That helps to reduce a lot of time that has to spend on testing. To run UI tests you need emulators or remotely accessible devices. You may aware that running the Android emulator is not currently supported on CircleCI 2.0, since it's not supported by the type of virtualization CircleCI uses on Linux. So they are suggesting to use external service like Firebase TestLab. If you developed your app with Flutter then Firebase TestLab is not an option since Firebase TestLab not supports for flutter test UI execution. For my recent flutter project, I needed to configure CircleCI for Flutter UI test execution. Even CircleCI Linux instance, not support for the android emulator, with MacOS instance we can run the emulator. Since we can build both Android and iOS builds in MacOS instance it's worth giv...