Inject test-helpers in the test-app

Author: NullVoxPopuli

test-app/package.json

@@ -22,6 +22,11 @@
     "test": "ember test",
     "test:ember": "ember test"
   },
+  "dependenciesMeta": {
+    "@ember/test-helpers": {
+      "injected": true
+    }
+  },
   "devDependencies": {
     "@babel/eslint-parser": "^7.21.3",
     "@babel/plugin-proposal-decorators": "^7.21.0",