vscode/test/smoke/README.md

VS Code Smoke Test

Make sure you are on Node v12.x.

Quick Overview

# Build extensions in the VS Code repo (if needed)
npm i && npm run compile

# Dev (Electron)
npm run smoketest

# Dev (Web - Must be run on distro)
npm run smoketest -- --web --browser [chromium|webkit]

# Build (Electron)
npm run smoketest -- --build <path to latest version>
example: npm run smoketest -- --build /Applications/Visual\ Studio\ Code\ -\ Insiders.app

# Build (Web - read instructions below)
npm run smoketest -- --build <path to server web build (ends in -web)> --web --browser [chromium|webkit]

# Remote (Electron)
npm run smoketest -- --build <path to latest version> --remote

* This step is necessary only when running without --build and OSS doesn't already exist in the .build/electron directory.

Running for a release (Endgame)

You must always run the smoketest version that matches the release you are testing. So, if you want to run the smoketest for a release build (e.g. release/1.22), you need to check out that version of the smoke tests too:

git fetch
git checkout release/1.22
npm i && npm run compile
cd test/smoke
npm i

Web

There is no support for testing an old version to a new one yet. Instead, simply configure the --build command line argument to point to the absolute path of the extracted server web build folder (e.g. <rest of path here>/vscode-server-darwin-x64-web for macOS). The server web build is available from the builds page (see previous subsection).

macOS: if you have downloaded the server with web bits, make sure to run the following command before unzipping it to avoid security issues on startup:

xattr -d com.apple.quarantine <path to server with web folder zip>

Note: make sure to point to the server that includes the client bits!

Debug

• --verbose logs all the low level driver calls made to Code;
• -f PATTERN (alias -g PATTERN) filters the tests to be run. You can also use pretty much any mocha argument;
• --headless will run playwright in headless mode when --web is used.

Note: you can enable verbose logging of playwright library by setting a DEBUG environment variable before running the tests (https://playwright.dev/docs/debug#verbose-api-logs), for example to pw:browser.

Develop

cd test/smoke
npm run watch

Troubleshooting

Error: Could not get a unique tmp filename, max tries reached

On Windows, check for the folder C:\Users\<username>\AppData\Local\Temp\t. If this folder exists, the tmp module can't run properly, resulting in the error above. In this case, delete the t folder.

Pitfalls

• Beware of workbench state. The tests within a single suite will share the same state.

• Beware of singletons. This evil can, and will, manifest itself under the form of FS paths, TCP ports, IPC handles. Whenever writing a test, or setting up more smoke test architecture, make sure it can run simultaneously with any other tests and even itself. All test suites should be able to run many times in parallel.

• Beware of focus. Never depend on DOM elements having focus using .focused classes or :focus pseudo-classes, since they will lose that state as soon as another window appears on top of the running VS Code window. A safe approach which avoids this problem is to use the waitForActiveElement API. Many tests use this whenever they need to wait for a specific element to have focus.

• Beware of timing. You need to read from or write to the DOM... but is it the right time to do that? Can you 100% guarantee that input box will be visible at that point in time? Or are you just hoping that it will be so? Hope is your worst enemy in UI tests. Example: just because you triggered Quick Access with F1, it doesn't mean that it's open and you can just start typing; you must first wait for the input element to be in the DOM as well as be the current active element.

• Beware of waiting. Never wait longer than a couple of seconds for anything, unless it's justified. Think of it as a human using Code. Would a human take 10 minutes to run through the Search viewlet smoke test? Then, the computer should even be faster. Don't use setTimeout just because. Think about what you should wait for in the DOM to be ready and wait for that instead.