How to access a struct array through a pointer?

Following are my 2 structs

type Attempt struct {
	StartTime        string `json:"startTime"`
	EndTime          string `json:"endTime"`
	LastUpdated      string `json:"lastUpdated"`
	Duration         uint32 `json:"duration"`
	SparkUser        string `json:"sparkUser"`
	IsCompleted      bool   `json:"completed"`
	LastUpdatedEpoch int64  `json:"lastUpdatedEpoch"`
	StartTimeEpoch   int64  `json:"startTimeEpoch"`
	EndTimeEpoch     int64  `json:"EndTimeEpoch"`
}

type Apps struct {
	Id       string    `json:"id"`
	Name     string    `json:"name"`
	Attempts []Attempt `json:"attempts"`
}

The following test parses a json string into this apps := &[]Apps{}. When accessing the members of apps, I am getting the following error

invalid operation: apps[0] (type *[]Apps does not support indexing)

The test

func TestUnmarshalApps(t *testing.T) {
	appsJson := `[
	  {
	    "id": "app-20161229224238-0001",
	    "name": "Spark shell",
	    "attempts": [
	      {
		"startTime": "2016-12-30T03:42:26.828GMT",
		"endTime": "2016-12-30T03:50:05.696GMT",
		"lastUpdated": "2016-12-30T03:50:05.719GMT",
		"duration": 458868,
		"sparkUser": "esha",
		"completed": true,
		"endTimeEpoch": 1483069805696,
		"lastUpdatedEpoch": 1483069805719,
		"startTimeEpoch": 1483069346828
	      },
	      {
		"startTime": "2016-12-30T03:42:26.828GMT",
		"endTime": "2016-12-30T03:50:05.696GMT",
		"lastUpdated": "2016-12-30T03:50:05.719GMT",
		"duration": 458868,
		"sparkUser": "esha",
		"completed": true,
		"endTimeEpoch": 1483069805696,
		"lastUpdatedEpoch": 1483069805719,
		"startTimeEpoch": 1483069346828
	      }
	    ]
	  },
	  {
	    "id": "app-20161229222707-0000",
	    "name": "Spark shell",
	    "attempts": [
	      {
		"startTime": "2016-12-30T03:26:50.679GMT",
		"endTime": "2016-12-30T03:38:35.882GMT",
		"lastUpdated": "2016-12-30T03:38:36.013GMT",
		"duration": 705203,
		"sparkUser": "esha",
		"completed": true,
		"endTimeEpoch": 1483069115882,
		"lastUpdatedEpoch": 1483069116013,
		"startTimeEpoch": 1483068410679
	      }
	    ]
	  }
	]`
	apps := &[]Apps{}
	err := json.Unmarshal([]byte(appsJson), apps)
	if err != nil {
		t.Fatal(err)
	}
	if len(*apps) != 2 {
		t.Fail()
	}

	if len(apps[0].Attempts) != 2 {
		t.Fail()
	}
}

How to access the fields Attempts, Id etc.?

apps := &[]Apps{}

apps has type *[]Apps (pointer to slice of Apps objects).

Are you sure you didn't mean to use the type []*Apps (slice of pointers to Apps objects)?

Assuming *[]Apps really is the type you intended, you'd need to use (*apps)[i] to access every element of apps. That type is also the reason why you also need to use len(*apps) instead of len(apps) (and *apps for pretty much everything actually).