chromium/chromeos/components/test/data/onc/policy/policy_wifi1_autoconnect.onc

{
  "NetworkConfigurations": [
    {
      "GUID": "policy_wifi1",
      "Type": "WiFi",
      "Name": "Managed wifi1",
      "WiFi": {
        "AutoConnect": true,
        "Passphrase": "policy's passphrase",
        "Recommended": [ "Passphrase" ],
        "SSID": "wifi1",
        "Security": "WPA-PSK"
      }
    }
  ],
  "Type": "UnencryptedConfiguration"
}