added the first grpc test, initially using the gprc gem stub client

Gemfile

@@ -37,6 +37,11 @@ group :test do
     gem "brotli"
     gem "ed25519"
     gem "net-ssh-gateway"
+
+    if RUBY_VERSION >= "2.3"
+      gem "grpc"
+      gem "logging"
+    end
   end
 
   platform :mri_21 do

test/http_test.rb

@@ -29,6 +29,7 @@ class HTTPTest < Minitest::Test
   include Plugins::Stream
   include Plugins::AWSAuthentication
   include Plugins::Upgrade
+  include Plugins::GRPC unless RUBY_ENGINE == "jruby" || RUBY_VERSION < "2.3"
 
   def test_verbose_log
     log = StringIO.new

test/support/grpc_helpers.rb

@@ -0,0 +1,76 @@
+# frozen_string_literal: true
+
+begin
+  require "grpc"
+  require "logging"
+
+  # IF HTTPX_DEBUG ....
+  module GRPC
+    extend Logging.globally
+  end
+  Logging.logger.root.appenders = Logging.appenders.stdout
+  Logging.logger.root.level = :info
+  Logging.logger["GRPC"].level = :info
+  Logging.logger["GRPC::ActiveCall"].level = :info
+  Logging.logger["GRPC::BidiCall"].level = :info
+
+  module GRPCHelpers
+    include ::GRPC::Core::StatusCodes
+    include ::GRPC::Core::TimeConsts
+    include ::GRPC::Core::CallOps
+
+    private
+
+    def teardown
+      super
+      return unless @grpc_server
+
+      @grpc_server.shutdown_and_notify(from_relative_time(2))
+      @grpc_server.close
+      @grpc_server_th.join if @grpc_server_th
+    end
+
+    def run_request_response(resp, status, marshal: nil, server_args: {}, server_initial_md: {}, server_trailing_md: {})
+      @grpc_server = ::GRPC::Core::Server.new(server_args.merge("grpc.so_reuseport" => 0))
+
+      server_port = @grpc_server.add_http2_port("0.0.0.0:0", :this_port_is_insecure)
+
+      @grpc_server_th = wakey_thread do |notifier|
+        c = expect_server_to_be_invoked(notifier, metadata_to_send: server_initial_md, marshal: marshal)
+        begin
+          yield c
+        ensure
+          c.remote_send(resp)
+          c.send_status(status, status == OK ? "OK" : "NOK", true, metadata: server_trailing_md)
+          c.send(:set_input_stream_done)
+          c.send(:set_output_stream_done)
+        end
+      end
+
+      server_port
+    end
+
+    def wakey_thread(&blk)
+      n = ::GRPC::Notifier.new
+      t = Thread.new do
+        blk.call(n)
+      end
+      t.abort_on_exception = true
+      n.wait
+      t
+    end
+
+    def expect_server_to_be_invoked(notifier, metadata_to_send: nil, marshal: nil)
+      @grpc_server.start
+      notifier.notify(nil)
+      recvd_rpc = @grpc_server.request_call
+      recvd_call = recvd_rpc.call
+      recvd_call.metadata = recvd_rpc.metadata
+      recvd_call.run_batch(SEND_INITIAL_METADATA => metadata_to_send)
+      ::GRPC::ActiveCall.new(recvd_call, marshal, marshal, INFINITE_FUTURE, metadata_received: true)
+    end
+  end
+rescue LoadError
+  module GRPCHelpers
+  end
+end

test/support/requests/plugins/grpc.rb

@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+module Requests
+  module Plugins
+    module GRPC
+      include GRPCHelpers
+
+      def test_plugin_grpc_unary
+        no_marshal = proc { |x| x }
+
+        server_port = run_request_response("a_reply", OK, marshal: no_marshal) do |call|
+          assert call.remote_read == "a_request"
+          assert call.metadata["k1"] == "v1"
+          assert call.metadata["k2"] == "v2"
+        end
+
+        # stub = ::GRPC::ClientStub.new("localhost:#{server_port}",
+        #                             :this_channel_is_insecure)
+        # grpc = HTTPX.plugin(:grpc)
+        # # build service
+        # stub = grpc.build_stub("localhost:#{server_port}", :this_channel_is_insecure)
+        stub = ::GRPC::ClientStub.new("localhost:#{server_port}", :this_channel_is_insecure)
+
+        op = stub.request_response("an_rpc_method", "a_request", no_marshal, no_marshal, return_op: true, metadata: { k1: "v1", k2: "v2" })
+        # op.start_call if run_start_call_first
+        result = op.execute
+
+        assert result == "a_reply"
+      end
+    end
+  end
+end