Backup and end-to-end test!

preload.js

@@ -205,3 +205,17 @@ window.Signal.Workflow.MessageDataMigrator =
 // We pull this in last, because the native module involved appears to be sensitive to
 //   /tmp mounted as noexec on Linux.
 require('./js/spell_check');
+
+if (window.config.environment === 'test') {
+  /* eslint-disable global-require, import/no-extraneous-dependencies */
+  window.test = {
+    fs: require('fs'),
+    glob: require('glob'),
+    fse: require('fs-extra'),
+    tmp: require('tmp'),
+    path: require('path'),
+    basePath: __dirname,
+    attachmentsPath,
+  };
+  /* eslint-enable global-require, import/no-extraneous-dependencies */
+}