a better approach towards client testing

instrumentation/grpc/test/opentelemetry/instrumentation/grpc/interceptors/client_tracer_test.rb

@@ -0,0 +1,73 @@
+# frozen_string_literal: true
+
+# Copyright The OpenTelemetry Authors
+#
+# SPDX-License-Identifier: Apache-2.0
+
+require_relative '../../../../test_helper'
+require_relative '../../../../support/grpc_server_runner'
+
+describe OpenTelemetry::Instrumentation::Grpc::Interceptors::ClientTracer do
+  let(:instrumentation) { OpenTelemetry::Instrumentation::Grpc::Instrumentation.instance }
+  let(:exporter) { EXPORTER }
+  let(:request) { Support::Proto::PingRequest.new(value: 'Ping!') }
+  let(:server_runner) { Support::GrpcServerRunner.new }
+
+  before do
+    instrumentation.install
+    exporter.reset
+
+    # use a real gRPC server to avoid non-trivial mocks
+    server_port = server_runner.start
+    # create a client stub to interact with the server
+    @stub = Support::Proto::PingServer::Stub.new(
+      "localhost:#{server_port}",
+      :this_channel_is_insecure
+    )
+  end
+  after do
+    server_runner.stop
+  end
+
+  describe '#request_response' do
+    it 'registers a span' do
+      _(exporter.finished_spans.size).must_equal 0
+
+      @stub.request_response_ping(request)
+
+      _(exporter.finished_spans.size).must_equal 1
+    end
+
+    it 'sets expected kind' do
+      @stub.request_response_ping(request)
+
+      span = exporter.finished_spans.first
+
+      _(span).wont_be_nil
+      _(span.kind).must_equal(:client)
+    end
+
+    it 'sets expected name' do
+      @stub.request_response_ping(request)
+
+      span = exporter.finished_spans.first
+
+      _(span).wont_be_nil
+      _(span.name).must_equal('support.proto.PingServer/RequestResponsePing')
+    end
+
+    it 'sets expected attributes' do
+      @stub.request_response_ping(request)
+
+      span = exporter.finished_spans.first
+
+      _(span).wont_be_nil
+      _(span.attributes['rpc.system']).must_equal('grpc')
+      _(span.attributes['rpc.service']).must_equal('support.proto.PingServer')
+      _(span.attributes['rpc.method']).must_equal('RequestResponsePing')
+      _(span.attributes['rpc.type']).must_equal('request_response')
+      _(span.attributes['net.sock.peer.addr']).wont_be_empty
+      _(span.attributes['rpc.grpc.status_code']).must_equal(0)
+    end
+  end
+end