Use Sourcery to automatically generate LinuxMain.swift with lists of tests

[BalestraPatrick]

Seems like this is a nice starting point: https://github.com/nodes-vapor/sourcery-templates

[meghankane]

I'd like to try to add support for this! :) Would you mind assigning this to me @BalestraPatrick ?

[BalestraPatrick]

Hey @meghaphone! Just invited you as collaborator, feel free to assign it to yourself 👍

[meghankane]

Awesome! Thanks

[BalestraPatrick]

If anyone is interested in implementing this, it's still not implemented.

[moritzsternemann]

I'd like to work on this 😄

[BalestraPatrick]

Awesome @moritzsternemann, let me know if you need any help!

[moritzsternemann]

I never used sourcery before but I guess assuming the command line tool is installed, mentioning the process in README and configuring via `.sourcery.yml' is the way to go here.

[moritzsternemann]

While researching this I just found out that with Swift 4.1 the SwiftPM added a command to generate and update the LinuxMain.swift (swiftlang/swift-package-manager#1485).
I got it to work with some small adjustments to the test case setup and I think this is a better solution than adding another dependency.

When SwiftPM generates the LinuxMain.swift it thinks the TestCase class is a test case itself and fails because that's an invalid test case name. I changed the class to a protocol and adopted it in all test case files.

Let me know what you think about this solution 🙃

[BalestraPatrick]

@moritzsternemann The problem with that as stated in the SPM PR is that it only works on macOS. Our CI runs on Linux on CircleCI so the LinuxMain wouldn't be generated.

[moritzsternemann]

Alright, using sourcery 👌

[kimdv]

Now on staging

Fixed in #155