Fix gRPC custom handler test

spec/ddtrace/contrib/grpc/datadog_interceptor/server_spec.rb

@@ -24,12 +24,12 @@
   end
 
   shared_examples 'span data contents' do
-    specify { expect(span.name).to eq 'grpc.service' }
-    specify { expect(span.span_type).to eq 'web' }
-    specify { expect(span.service).to eq 'rspec' }
-    specify { expect(span.resource).to eq 'my.server.endpoint' }
-    specify { expect(span.get_tag('error.stack')).to be_nil }
-    specify { expect(span.get_tag(:some)).to eq 'datum' }
+    it { expect(span.name).to eq 'grpc.service' }
+    it { expect(span.span_type).to eq 'web' }
+    it { expect(span.service).to eq 'rspec' }
+    it { expect(span.resource).to eq 'my.server.endpoint' }
+    it { expect(span.get_tag('error.stack')).to be_nil }
+    it { expect(span.get_tag(:some)).to eq 'datum' }
 
     it_behaves_like 'analytics for integration' do
       let(:analytics_enabled_var) { Datadog::Contrib::GRPC::Ext::ENV_ANALYTICS_ENABLED }
@@ -48,11 +48,46 @@
         method: instance_double(Method, owner: 'My::Server', name: 'endpoint') }
     end
 
-    before do
-      subject.request_response(**keywords) {}
+    it_behaves_like 'span data contents' do
+      before do
+        subject.request_response(**keywords) {}
+      end
     end
 
-    it_behaves_like 'span data contents'
+    context 'with an error' do
+      subject(:request_response) do
+        server.request_response(**keywords) { raise error_class, 'test error' }
+      end
+
+      let(:error_class) { stub_const('TestError', Class.new(StandardError)) }
+
+      context 'without an error handler' do
+        it do
+          expect { request_response }.to raise_error('test error')
+
+          expect(span).to have_error
+          expect(span).to have_error_message('test error')
+          expect(span).to have_error_type('TestError')
+          expect(span).to have_error_stack(include('server_spec.rb'))
+        end
+      end
+
+      context 'with an error handler' do
+        let(:configuration_options) { { service_name: 'rspec', error_handler: error_handler } }
+        let(:error_handler) do
+          lambda do |span, error|
+            span.set_tag('custom.handler', "Got error #{error}, but ignored it")
+          end
+        end
+
+        it do
+          expect { request_response }.to raise_error('test error')
+
+          expect(span).to_not have_error
+          expect(span.get_tag('custom.handler')).to eq('Got error test error, but ignored it')
+        end
+      end
+    end
   end
 
   describe '#client_streamer' do
@@ -95,15 +130,4 @@
 
     it_behaves_like 'span data contents'
   end
-
-  describe '#error_handler' do
-    let(:error_handler) { proc { |span, error| span.set_error(error) if error.is_a?(StandardError) } }
-    let(:configuration_options) { { service_name: 'rspec', on_error: error_handler } }
-
-    before do
-      subject.request_response(**keywords) { raise 'error' }
-    end
-
-    it { expect(span).to have_error }
-  end
 end