"Module was not compiled for testing" error when using Swift Package Manager

Question

I created a Swift library with swift package init --type library and generated an Xcode project with swift package generate-xcodeproj.

Now I'm trying to run the Test scheme in Xcode. It prints following error:

Module '<title>' was not compiled for testing

However when I run swift build and swift test in terminal, it works fine.

I have ENABLE_TESTABILITY set to YES in all of the targets. I didn't change anything in the project except this. How can I make Xcode perform unit testing?

Answer 1

You need to set the "Enable Testability" to Yes in build setting over your "Main Target"

Answer 2

I was having this issue today, it seems like @testable cannot be used with projects generated by Swift Package Manager.

Removing @testable from my import statements solved this issue. Of course, this means we can only test the public interface of our modules.