added the rate limiter tests

lib/httpx/plugins/rate_limiter.rb

@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+module HTTPX
+  module Plugins
+    #
+    # This plugin adds support for retrying requests when the request:
+    #
+    # * is rate limited;
+    # * when the server is unavailable (503);
+    # * when a 3xx request comes with a "retry-after" value
+    #
+    # https://gitlab.com/honeyryderchuck/httpx/wikis/RateLimiter
+    #
+    module RateLimiter
+    end
+
+    register_plugin :rate_limiter, RateLimiter
+  end
+end

test/http_test.rb

@@ -25,6 +25,7 @@ class HTTPTest < Minitest::Test
   include Plugins::Retries
   include Plugins::Multipart
   include Plugins::Expect
+  include Plugins::RateLimiter
 
   def test_verbose_log
     log = StringIO.new

test/https_test.rb

@@ -25,6 +25,7 @@ class HTTPSTest < Minitest::Test
   include Plugins::Retries
   include Plugins::Multipart
   include Plugins::Expect
+  include Plugins::RateLimiter
 
   def test_connection_coalescing
     coalesced_origin = "https://#{ENV["HTTPBIN_COALESCING_HOST"]}"

test/support/requests/plugins/rate_limiter.rb

@@ -0,0 +1,73 @@
+# frozen_string_literal: true
+
+module Requests
+  module Plugins
+    module RateLimiter
+      def test_plugin_rate_limiter_429
+        rate_limiter_session = HTTPX.plugin(RequestInspector)
+                                    .plugin(SessionWithMockResponse[429])
+                                    .plugin(:rate_limiter)
+
+        uri = build_uri("/get")
+
+        rate_limiter_session.get(uri)
+
+        verify_rated_responses(rate_limiter_session, 429)
+      end
+
+      def test_plugin_rate_limiter_503
+        rate_limiter_session = HTTPX.plugin(RequestInspector)
+                                    .plugin(SessionWithMockResponse[503])
+                                    .plugin(:rate_limiter)
+
+        uri = build_uri("/get")
+
+        rate_limiter_session.get(uri)
+
+        verify_rated_responses(rate_limiter_session, 503)
+      end
+
+      def test_plugin_rate_limiter_retry_after_integer
+        rate_limiter_session = HTTPX.plugin(RequestInspector)
+                                    .plugin(SessionWithMockResponse[429, "retry-after" => "2"])
+                                    .plugin(:rate_limiter)
+
+        uri = build_uri("/get")
+
+        before_time = Process.clock_gettime(Process::CLOCK_MONOTONIC, :second)
+        rate_limiter_session.get(uri)
+        after_time = Process.clock_gettime(Process::CLOCK_MONOTONIC, :second)
+
+        verify_rated_responses(rate_limiter_session, 429)
+
+        total_time = after_time - before_time
+        assert_in_delta 2, total_time, 1, "request didn't take as expected to retry (#{total_time} secs)"
+      end
+
+      def test_plugin_rate_limiter_retry_after_date
+        rate_limiter_session = HTTPX.plugin(RequestInspector)
+                                    .plugin(SessionWithMockResponse[429, "retry-after" => (Time.now + 3).httpdate])
+                                    .plugin(:rate_limiter)
+
+        uri = build_uri("/get")
+
+        before_time = Process.clock_gettime(Process::CLOCK_MONOTONIC, :second)
+        rate_limiter_session.get(uri)
+        after_time = Process.clock_gettime(Process::CLOCK_MONOTONIC, :second)
+
+        verify_rated_responses(rate_limiter_session, 429)
+        total_time = after_time - before_time
+        assert_in_delta 3, total_time, 1, "request didn't take as expected to retry (#{total_time} secs)"
+      end
+
+      private
+
+      def verify_rated_responses(session, rated_status)
+        assert session.total_responses.size == 2, "expected 2 responses(was #{session.total_responses.size})"
+        rated_response, response = session.total_responses
+        verify_status(rated_response, rated_status)
+        verify_status(response, 200)
+      end
+    end
+  end
+end