How to make a function only callable from tests?

taylorswift · 2024-02-19T21:41:29.563Z

i have a function that is defined like this:

extension Outliner
{
    @_spi(testable)
    public consuming
    func outlines() -> [Outline]
    {
        self.cache.clear()
    }
}

it is gated by the @_spi(testable) already, but i want to go even further and prevent this function from being called from within the module in which it resides, as its only purpose is to provide a testing hook for checking assertions. what is the best way to do this?

MPLewis · 2024-02-20T00:58:31.105Z

I think you can gate compilation on if XCTest can be imported, but I haven’t tried it in a while:

#if canImport(XCTest)
…
#endif

taylorswift · 2024-02-20T03:30:25.652Z

alas, these test targets are not true SPM test targets, rather they are just ordinary executableTargets.

somu · 2024-02-20T05:23:39.176Z

Just wondering if it would make sense to create an extension in your test target and add that function outlines?

MPLewis · 2024-02-20T07:52:45.719Z

Could you just have a custom define on that target that accomplishes the same thing then? .executableTarget's swiftSettings argument has a .define factory method.

maartene · 2024-02-20T08:16:38.429Z

Curious as well how this can be solved.

taylorswift · 2024-02-21T20:09:21.751Z

MPLewis:

Could you just have a custom define on that target that accomplishes the same thing then? .executableTarget's swiftSettings argument has a .define factory method.

this was one of the first things i tried, but the define flags only affect the target they are applied to; they are not recursively propagated to its dependencies.