added tests for connection refused behaviour

test/http_test.rb

@@ -14,6 +14,7 @@ class HTTPTest < Minitest::Test
   include ResponseBody
   include IO
   include Timeouts
+  include Errors
 
   include Plugins::Proxy
   include Plugins::Authentication
@@ -24,7 +25,7 @@ class HTTPTest < Minitest::Test
 
   private
 
-  def origin
-    "http://#{httpbin}"
+  def origin(orig=httpbin)
+    "http://#{orig}"
   end
 end

test/https_test.rb

@@ -12,6 +12,7 @@ class HTTPSTest < Minitest::Test
   include ResponseBody
   include IO
   include Timeouts
+  include Errors
 
   include Plugins::Proxy
   include Plugins::Authentication
@@ -22,7 +23,7 @@ class HTTPSTest < Minitest::Test
 
   private
 
-  def origin
-    "https://#{httpbin}"
+  def origin(orig=httpbin)
+    "https://#{orig}"
   end
 end

test/support/requests/errors.rb

@@ -0,0 +1,21 @@
+module Requests
+  module Errors
+
+    def test_connection_refused
+      unavailable_host = URI(origin('localhost'))
+      unavailable_host.port = next_available_port
+      response = HTTPX.get(unavailable_host.to_s)
+      assert response.is_a?(HTTPX::ErrorResponse), "response should contain errors"
+      assert response.status =~ /Connection refused/, "connection should have been refused"
+    end
+
+    private
+
+    def next_available_port
+      server = TCPServer.new('localhost', 0)
+      server.addr[1]
+    ensure
+      server.close
+    end
+  end
+end