如何验证我只从JSON响应中获得一个密钥？

Question

我在JSON中得到了一个响应,需要确保我在signal_events中只得到一个'信号'.我正在使用Ruby和rspec.

"signal_events": [
{
  "id": "587e9ae969702d10bd5a0000",
  "created_at": 1484692201,
  "geo": {
    "type": "Point",
    "coordinates": [
      -153.45703125,
      59.67773438
    ]
  },
  "expires_at": 1484778601,
  "geohashes": [
    "bddg",
    "bdeh"
  ],
  "signal": {
    "id": "587e9ae969702d0911060000",
    "created_at": 1484692201.24,
    "expires_at": 1484778601.24,
    "signal_at": 1484691607,
    "source": "usgs",
    "updated_at": 1484692144,
    "magnitude": 2,
    "radius": 6.36107901750268,
    "event_name": "earthquake",
    "tsunami": "no"
  },
  "signal_type": "earthquake",
  "centroid": {
    "type": "Point",
    "coordinates": [
      -153.45703125,
      59.67773438
    ]
  },
  "location": {
    "country": "United States",
    "country_code": "US",
    "city": "Kenai Peninsula Borough",
    "region": "Kenai Peninsula Borough",
    "region_code": "AK"
  }
},

Answer 1

哈希不能包含重复的键,因此对于任何给定的键,您将始终拥有一个值.