GitHub Actions is a relatively recent feature update to GitHub that allows you to run CI/CD tasks in response to repository changes. The service is free to public repositories and available to the paid tiers of private organizations.
One shortcoming I’ve encountered is that each version of Xcode only has the default shipping simulators available to it. Thus, if you want to do tests 1 or even 2 iOS versions back, you need to do some setup work. Thankfully, there is a solution less drastic than downloading the required simulator at the start of every CI run (which would slow things down terribly).
The solution comes from the fact that the default MacOS environment has many previous versions of Xcode available. You can use symbolic links to make an older simulator appear to be installed when you run xcodebuild. This can be done as a step just before you begin build / test operations:
[gist https://gist.github.com/JoshuaSullivan/8a1455bc9813b5926235053e1de8c93b]
You can see a complete list of software installed on the virtual MacOS environments on this page. You can see they maintain all current- and previous-generation versions of Xcode as well as one version from 2 generations ago. To pick a particular simulator, you just need to modify the workflow step to refer to the correct version of Xcode and name the linked simulator core appropriately.
To use the simulator, you simply need to update the destination flag of your xcodebuild command to look something like this:-destination 'platform=iOS Simulator,name=iPhone 11,OS=13.7'
The next time you run your workflow, you should see it link to the specified simulator and use it for your tests.