useInstallation.fromPath silently skips tests when VS Code is on a different Windows drive

[steve02081504]

Environment

• Windows 11
• Node.js v26.5.0
• @vscode/test-cli 0.0.10
• @vscode/test-electron 2.5.2
• VS Code 1.138.0 installed on E:\VS Code; the project lives on C:

Config

// .vscode-test.mjs
export default defineConfig({
  files: 'test/**/*.test.js',
  useInstallation: { fromPath: 'E:\\VS Code\\Code.exe' }
})

Steps to reproduce

1. Point useInstallation.fromPath at a VS Code executable that is on a different drive than the project (here E:, project on C:).
2. Run npx vscode-test.

Actual behavior

The command exits with code 0 but no tests are executed and no Mocha output is printed. In .vscode-test/user-data/logs/<session>/window1/exthost/exthost.log the extension under test is activated (activationEvent: 'api') and then the host terminates immediately:

Extension host with pid 12345 started
Extension host terminating: received terminate message from renderer
Extension host with pid 12345 exiting with code 0

Because runTests resolves with exit code 0, the failure is completely silent (CI would go green without running anything).

Expected behavior

Tests run, or at least a non-zero exit code / error is surfaced.

Workarounds that do work

• Passing the same installation through a junction on the project drive:
  C:\...\vscode-local -> E:\VS Code, then fromPath: 'C:\\...\\vscode-local\\Code.exe'.
• Omitting useInstallation entirely (a VS Code copy is downloaded onto the project drive and used).

Notes

innerRunTests (out/runTest.js) spawns the CLI resolved by resolveCliPathFromVSCodeExecutablePath (E:\VS Code\bin\code.cmd) with shell: true, adding --user-data-dir / --extensions-dir from getProfileArguments (both on C:). Something about the cross-drive combination makes that spawned process return immediately instead of hosting the tests. Keeping the executable and the profile directories on the same drive avoids it.

runTests resolving successfully while nothing ran also makes this hard to detect from a test script; an explicit "no tests were executed" check would help.

[steve02081504]

Downstream notes (ps12exe VS Code extension, .vscode-test.mjs).

Workaround currently used: after resolving the local VS Code executable, if it is on a different Windows drive than the project, we create a directory junction on the project drive and pass the junction's Code.exe to useInstallation.fromPath:

.vscode-test/vscode-local  ->  E:\VS Code
useInstallation: { fromPath: '<project>/.vscode-test/vscode-local/Code.exe' }

That makes the same installation work with no download.

When this is fixed upstream:

• Remove bridgeToProjectDrive() from .vscode-test.mjs and pass the executable resolved by where_command('code') directly.
• Keep the assertion/explicit "no tests were executed" guard if one is added upstream, so a silent skip can never make CI green.

[copilot-swe-agent]

The agent encountered an error and was unable to start working on this issue: Please try again later, or contact support if the problem persists. (Request id: 2D60:27CCC8:2134A52C:22898ACC:6AB15DEB)