Is it reproducible with SwiftPM command-line tools: swift build, swift test, swift package etc?

• Confirmed reproduction steps with SwiftPM CLI. The description text must include reproduction steps with either of command-line SwiftPM commands, swift build, swift test, swift package etc.

Description

When using SwiftBuild, swift-testing tests are not run (but XCTest looks to be fine).

Expected behavior

swift-testing tests to be run.

Actual behavior

swift-testing tests are not even recognized.

Steps to reproduce

The issue looks to be more broad, but this is how I bumped into it:

• Clone https://github.com/MahdiBM/swift-dns.
• I'm on branch mmbm-conn-pool but that likely doesn't matter.
• Try to run the tests with SwiftBuild: swift test --build-system=swiftbuild
• The package requires macOS 26 if on macOS.

Swift Package Manager version/commit hash

Swift Package Manager - Swift 6.2.0-dev

Swift & OS version (output of swift --version ; uname -a)

macOS+Xcode 26 beta 4 (but on VSCode/Cursor)

swift-driver version: 1.127.10 Apple Swift version 6.2 (swiftlang-6.2.0.14.8 clang-1700.3.14.6)
Target: arm64-apple-macosx26.0
Darwin my-pc 25.0.0 Darwin Kernel Version 25.0.0: Fri Jul 11 23:54:50 PDT 2025; root:xnu-12377.0.154.0.2~26/RELEASE_ARM64_T6000 arm64