Make sure the ca file exist.

Author: calavera

test/service_test.rb

@@ -10,6 +10,7 @@ def test_validates_events
   def test_default_path_to_ca_file
     s = CC::Service.new({}, {name: "test"})
     assert_equal(File.expand_path("../../config/cacert.pem", __FILE__), s.ca_file)
+    assert File.exist?(s.ca_file)
   end
 
   def test_custom_path_to_ca_file