Install Slack so we can run Electron tests in GHA

Author: pimterry

.github/workflows/ci.yml

@@ -31,7 +31,12 @@ jobs:
         run: |
           apt-get update
           apt-get install p7zip-full xterm
-          cp test/chrome-docker-wrapper.sh /usr/local/bin/google-chrome
+
+          wget https://downloads.slack-edge.com/linux_releases/slack-desktop-4.12.2-amd64.deb
+          apt install ./slack-desktop-4.12.2-amd64.deb
+
+          cp test/no-sandbox-docker-wrapper.sh /usr/local/bin/google-chrome
+          cp test/no-sandbox-docker-wrapper.sh /usr/local/bin/slack
 
           # Fix $HOME perms to make Firefox happy
           chown $(whoami) $HOME

test/chrome-docker-wrapper.sh

@@ -11,13 +11,14 @@ const interceptorSetup = setupInterceptor('electron');
 // We use slack as a test app. Doesn't really matter what it is, but
 // slack is pretty common, easy to kill & restart, and fairly representative.
 const electronAppPath: string | undefined = [
+    '/usr/local/bin/slack', // Wrapper, used in CI to inject --no-sandbox
     '/usr/bin/slack',
     '/Applications/Slack.app/Contents/MacOS/Slack',
     `${os.homedir()}\\AppData\\Local\\slack\\slack.exe`
 ].find((path) => fs.existsSync(path));
 
 describe('Electron interception', function () {
-    this.timeout(5000000);
+    this.timeout(5000);
 
     beforeEach(async () => {
         const { server } = await interceptorSetup;

test/interceptors/electron.spec.ts

@@ -0,0 +1,20 @@
+#!/bin/bash
+trap : SIGTERM SIGINT
+
+# We need to inject a --no-sandbox option, because inside Docker Chrome/Electron apps
+# can't start their sandbox, so without this it refuses to start at all.
+
+# It's assumed that this is copied/linked into a file in /usr/local/bin to wrap a
+# binary with the same name (e.g. google-chrome) in /usr/bin:
+/usr/bin/$(basename $0) --no-sandbox "$@" &
+APP_PID=$!
+
+wait $APP_PID
+
+WAIT_EXIT_CODE=$?
+
+# If this script gets killed, kill the app with the same signal
+if [[ WAIT_EXIT_CODE -gt 128 ]]
+then
+    kill -$(($WAIT_EXIT_CODE - 128)) $APP_PID
+fi