Introduce custom assertion

test/models/epp/response_test.rb

@@ -0,0 +1,29 @@
+require 'test_helper'
+
+class EppResponseTest < ActiveSupport::TestCase
+  def test_creates_new_response_from_xml_doc
+    xml = <<-XML
+      <?xml version="1.0" encoding="UTF-8"?>
+      <epp xmlns="https://epp.tld.ee/schema/epp-ee-1.0.xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="lib/schemas/epp-ee-1.0.xsd">
+        <response>
+          <result code="1000">
+            <msg>any</msg>
+          </result>
+        </response>
+      </epp>
+    XML
+
+    assert_kind_of Epp::Response, Epp::Response.xml(xml)
+  end
+
+  def test_code_predicate
+    present_code = Epp::Response::Result::Code.key(:completed_successfully)
+    absent_code = Epp::Response::Result::Code.key(:required_parameter_missing)
+
+    result = Epp::Response::Result.new(code: present_code)
+    response = Epp::Response.new(results: [result])
+
+    assert response.code?(present_code)
+    assert_not response.code?(absent_code)
+  end
+end