Default to nulls and update tests

package-lock.json

@@ -71,6 +71,7 @@
         "@types/serve-handler": "^6.1.4",
         "@vitejs/plugin-react": "^4.3.2",
         "autoprefixer": "^10.4.20",
+        "co": "^4.6.0",
         "eslint": "^9.11.1",
         "eslint-plugin-react-hooks": "^5.1.0-rc.0",
         "eslint-plugin-react-refresh": "^0.4.12",
@@ -4800,6 +4801,17 @@
         "react-dom": "^18 || ^19 || ^19.0.0-rc"
       }
     },
+    "node_modules/co": {
+      "version": "4.6.0",
+      "resolved": "https://registry.npmjs.org/co/-/co-4.6.0.tgz",
+      "integrity": "sha512-QVb0dM5HvG+uaxitm8wONl7jltx8dqhfU33DcqtOZcLSVIKSDDLDi7+0LbAKiyI8hD9u42m2YxXSkMGWThaecQ==",
+      "dev": true,
+      "license": "MIT",
+      "engines": {
+        "iojs": ">= 1.0.0",
+        "node": ">= 0.12.0"
+      }
+    },
     "node_modules/color-convert": {
       "version": "2.0.1",
       "resolved": "https://registry.npmjs.org/color-convert/-/color-convert-2.0.1.tgz",