basic-multi-root-sample/.vscode/launch.json

// A launch configuration that compiles the extension and then opens it inside a new window
{
    "version": "0.2.0",
    "configurations": [
        {
            "name": "Launch Extension",
            "type": "extensionHost",
            "request": "launch",
            "runtimeExecutable": "${execPath}",
            "args": ["--extensionDevelopmentPath=${workspaceRoot}" ],
            "stopOnEntry": false,
            "sourceMaps": true,
            "outFiles": [ "${workspaceRoot}/out/src/**/*.js" ],
            "preLaunchTask": "npm: watch"
        },
        {
            "name": "Launch Tests",
            "type": "extensionHost",
            "request": "launch",
            "runtimeExecutable": "${execPath}",
            "args": ["--extensionDevelopmentPath=${workspaceRoot}", "--extensionTestsPath=${workspaceRoot}/out/test" ],
            "stopOnEntry": false,
            "sourceMaps": true,
            "outFiles": [ "${workspaceRoot}/out/test/**/*.js" ],
            "preLaunchTask": "npm: watch"
        }
    ]
}