Building in release mode produces this since #410 was merged: ``` > ./swift-5.6.2-RELEASE-ubuntu20.04/usr/bin/swift build -c release /home/butta/swift-argument-parser/Sources/ArgumentParserTestHelpers/TestHelpers.swift:12:18: error: module 'ArgumentParser' was not compiled for testing @testable import ArgumentParser ``` That means the last working version was 1.0.3. A workaround is to add `-Xswiftc -enable-testing`. **ArgumentParser version:** latest commit df9ee66 from the `main` branch **Swift version:** 5.5 and later, probably earlier versions too ### Checklist - [x] If possible, I've reproduced the issue using the `main` branch of this package - [x] I've searched for [existing GitHub issues](https://github.com/apple/swift-argument-parser/issues)