test: Add metrics unit test

waku/metrics/http.go

@@ -69,13 +69,16 @@ func NewMetricsServer(address string, port int) *Server {
 
 // Start executes the HTTP server in the background.
 func (p *Server) Start() {
-	log.Info("Server stopped ", p.server.ListenAndServe())
+	log.Info("server stopped ", p.server.ListenAndServe())
 }
 
 // Stop shuts down the prometheus server
-func (p *Server) Stop(ctx context.Context) {
+func (p *Server) Stop(ctx context.Context) error {
 	err := p.server.Shutdown(ctx)
 	if err != nil {
-		log.Error("Server shutdown err", err)
+		log.Error("error while stopping server", err)
+		return err
 	}
+
+	return nil
 }

waku/metrics/http_test.go

@@ -0,0 +1,21 @@
+package metrics
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestStartAndStopMetricsServer(t *testing.T) {
+	server := NewMetricsServer("0.0.0.0", 9876)
+
+	go func() {
+		time.Sleep(1 * time.Second)
+		err := server.Stop(context.Background())
+		require.NoError(t, err)
+	}()
+
+	server.Start()
+}

waku/node.go

@@ -233,7 +233,8 @@ func Execute(options Options) {
 	wakuNode.Stop()
 
 	if options.Metrics.Enable {
-		metricsServer.Stop(ctx)
+		err = metricsServer.Stop(ctx)
+		failOnErr(err, "MetricsClose")
 	}
 
 	if options.UseDB {