Thank you, it seems that I can do this using the linkedFramework you show above:
swift build -Xswiftc -FFrameworks/Build/iOS
swift test -Xswiftc -FFrameworks/Build/iOS
And it finds my frameworks, linking into the main app is similar in that I can add the frameworks path in the Xcode target. Alternatively, in the manifest:
swiftSettings: [
.unsafeFlags(["-FFrameworks/build/iOS"]),
]
and the command:
swift build
This will work for now, but hope the discussion "SPM Support for Binaries Distribution - #21 by ddunbar" leads to something longer term. UnsafeFlags seems like it won't work past development phase.