skip android test fails to find test binary with swift-build system in swift 6.4

[marcprux]

When running against the latest nightly preview (swift-DEVELOPMENT-SNAPSHOT-2026-04-30-a_android) of the 6.4 swift-build overhaul, running test cases against Android fails:

zap apple/swift-algorithms [main] % skip android test

Fetching https://github.com/apple/swift-numerics.git from cache
Fetched https://github.com/apple/swift-numerics.git from cache (0.24s)
Computing version for https://github.com/apple/swift-numerics.git
Computed https://github.com/apple/swift-numerics.git at 1.0.2 (0.90s)
Creating working copy for https://github.com/apple/swift-numerics.git
Working copy of https://github.com/apple/swift-numerics.git resolved at 1.0.2
Building for debugging...
Pre-planning 1 / 183
Planning deferred tasks
[56/100] RealModule 46 / 78
[57/100] _NumericsShims 47 / 78
[60/100] RealModule 49 / 78
[60/100] Algorithms 57 / 90
[64/100] Algorithms 60 / 90
[67/100] Algorithms 63 / 90
[68/100] Algorithms 64 / 90
[69/100] RealModule 65 / 91
[73/100] Algorithms 68 / 91
[73/100] Algorithms 68 / 92
[80/100] SwiftAlgorithmsTests-product 86 / 104
[81/100] SwiftAlgorithmsTests-product 87 / 104
[88/100] Algorithms 92 / 104
[89/100] SwiftAlgorithmsTests-product 93 / 104
[91/100] SwiftAlgorithmsTests-product 96 / 105
[92/100] SwiftAlgorithmsTests-product 97 / 105
[93/100] SwiftAlgorithmsTests-test-runner 101 / 108
[97/100] SwiftAlgorithmsTests-test-runner 105 / 108
[99/100] SwiftAlgorithmsTests-test-runner 108 / 109
[100/100] SwiftAlgorithmsTests-test-runner 109 / 109
[100/100] 
Build complete! (143.78 sec)
[✓] Check Swift Package (1.28s)

Error: Expected executable did not exist at: /opt/src/github/apple/swift-algorithms/.build/aarch64-unknown-linux-android28/debug/swift-algorithmsPackageTests.xctest

The issue is that the location for the built executable has changed in swift-build, from:

.build/debug/swift-algorithmsPackageTests.xctest -> .build/aarch64-unknown-linux-android28/debug/swift-algorithmsPackageTests.xctest

to the symlink'd:

.build/debug/SwiftAlgorithmsTests-test-runner -> .build/out/Products/Debug-android/SwiftAlgorithmsTests-test-runner

It remains to be seen whether there are other issues with this new location, and whether there are any consequences to the target triple no longer being included in the build output path.

[marcprux]

The layout change has caused breakage elsewhere (see vapor/swift-codecov-action#5).

[marcprux]

As recommended at swiftlang/swift-package-manager#9963 (comment), we might use swift build --show-bin-path to find the right folder. E.g.:

Swift 6.3:

$ swiftly run swift build --show-bin-path +6.3
/opt/src/github/apple/swift-algorithms/.build/arm64-apple-macosx/debug

$ swiftly run swift build --show-bin-path --swift-sdk x86_64-unknown-linux-android28 +6.3
/opt/src/github/apple/swift-algorithms/.build/x86_64-unknown-linux-android28/debug

Swift 6.4 (swift-build):

$ swiftly run swift build --show-bin-path +swift-DEVELOPMENT-SNAPSHOT-2026-04-30-a
/opt/src/github/apple/swift-algorithms/.build/out/Products/Debug

$ swiftly run swift build --show-bin-path --swift-sdk x86_64-unknown-linux-android28 +swift-DEVELOPMENT-SNAPSHOT-2026-04-30-a
/opt/src/github/apple/swift-algorithms/.build/out/Products/Debug-android