Added test for Tempfiles

Author: cacheflow

spec/fcm_spec.rb

@@ -1,4 +1,5 @@
 require "spec_helper"
+require 'tempfile'
 
 describe FCM do
   let(:project_name) { 'test-project' }
@@ -75,6 +76,14 @@
     it 'can be an IO object' do
       fcm = FCM.new(StringIO.new('hey'))
       expect(fcm.__send__(:json_key).class).to eq(StringIO)
+
+      temp_file = Tempfile.new('hello_world.json')
+      temp_file.write(json_credentials)
+      fcm_with_temp_file = FCM.new(temp_file)
+
+      expect { fcm_with_temp_file.__send__(:json_key) }.not_to raise_error(creds_error)
+      temp_file.close
+      temp_file.unlink
     end
 
     it 'raises an error when passed a non IO-like object' do