Add tests for new API

spec/controllers/api/v1/devices_controller_spec.rb

+require 'rails_helper'
+
+RSpec.describe Api::V1::DevicesController, type: :controller do
+  let(:user)  { Fabricate(:user, account: Fabricate(:account, username: 'alice')) }
+  let(:token) { double acceptable?: true, resource_owner_id: user.id }
+
+  before do
+    allow(controller).to receive(:doorkeeper_token) { token }
+  end
+
+  describe 'POST #register' do
+    before do
+      post :register, params: { registration_id: 'foo123' }
+    end
+
+    it 'returns http success' do
+      expect(response).to have_http_status(:success)
+    end
+
+    it 'registers device' do
+      expect(Device.where(account: user.account, registration_id: 'foo123').first).to_not be_nil
+    end
+  end
+
+  describe 'POST #unregister' do
+    before do
+      post :unregister, params: { registration_id: 'foo123' }
+    end
+
+    it 'returns http success' do
+      expect(response).to have_http_status(:success)
+    end
+
+    it 'removes device' do
+      expect(Device.where(account: user.account, registration_id: 'foo123').first).to be_nil
+    end
+  end
+end