Add Test Bundle for iOS and macOS

[winsmith]

• [ ] Find out how to retroactively add a Unit Test Bundle to an Xcode Project
• [ ] Find out how to retroactively add a UI Test Bundle to an Xcode Project
• [ ] Add Unit Tests to the Project
• [ ] Add UI Tests to the Project
• [ ] Add 1 random UI test
• [ ] Add 1 random Unit test