EndToEnd tests deadlock when run at the command line with swift test

[euanh]

The EndToEnd tests are commented out on macOS. Uncommenting them shows that they run from Xcode, but block forever when run from the command line with swift test.

The end to end tests try to run the generator by executing swift run swift-sdk-generator.

swift-sdk-generator/Tests/SwiftSDKGeneratorTests/EndToEndTests.swift

Lines 59 to 61 in bde8791

	let generatorOutput = try await Shell.readStdout(
	"cd \(packageDirectory) && swift run swift-sdk-generator \(runArguments)"
	)

However the tests themselves are being run within within an existing Swift Package Manager instance which already has a lock on the .build directory, so the test run deadlocks.

We can verify this by redirecting the generator command output to a file:

      let generatorOutput = try await Shell.readStdout(
        "cd \(packageDirectory) && swift run swift-sdk-generator \(runArguments) > stdout 2> stderr"
      )

stderr shows that the swift run command executed by the test is blocked:

% cat Tests/stderr
Another instance of SwiftPM is already running using '/tmp/test/swift-sdk-generator/.build', waiting until that process has finished execution...

[euanh]

Setting a different scratch path helps avoid a conflict between the two Swift Package Manager instances:

  --scratch-path <scratch-path>    Specify a custom scratch directory path (default .build)

There may still some other problems to resolve, though.