Add heartbeat model, next_heartbeat_time and update_heartbeat_time on device registration

spec/factories/heartbeats.rb

@@ -0,0 +1,6 @@
+FactoryGirl.define do
+  factory :heartbeat do
+    association :device
+  end
+
+end

spec/models/device_spec.rb

@@ -1,7 +1,7 @@
 require 'rails_helper'
 
 RSpec.describe Device, type: :model do
-  let(:device) { create(:device) }
+  let!(:device) { create(:device) }
 
   it { should validate_presence_of :unique_id }
   it { should validate_presence_of :model }
@@ -12,4 +12,14 @@ RSpec.describe Device, type: :model do
       expect(device.access_token).not_to be_nil
     end
   end
+
+  describe "heartbeat" do
+    it "last heartbeat time to updated with updated_at time" do
+      expect(Device.last.last_heartbeat_recd_time).not_to be_nil
+    end
+
+    it "next hearbeat time" do
+      expect(Device.last.next_heartbeat_time).not_to be_nil
+    end
+  end
 end

spec/models/heartbeat_spec.rb

@@ -0,0 +1,15 @@
+require 'rails_helper'
+
+RSpec.describe Heartbeat, type: :model do
+  let(:heartbeat){create(:heartbeat)}
+  
+  it "update device  heartbeat details" do
+    device = heartbeat.device
+    expect(device.last_heartbeat_recd_time).to eq(heartbeat.created_at)
+    expect(device.heartbeats_count).to eq(1)
+  end
+
+  it "next heartbeat" do
+    expect(heartbeat.next_heartbeat_time).not_to be_nil
+  end
+end