diff --git a/pkg/metrics/metrics.go b/pkg/metrics/metrics.go
index 24bcdd7ca..8ba988914 100644
--- a/pkg/metrics/metrics.go
+++ b/pkg/metrics/metrics.go
@@ -163,11 +163,17 @@ func (c *Collector) Matches(glob string) bool {
 	}
 
 	ok, err := path.Match(glob, c.group)
+	if err != nil {
+		log.Warnf("invalid glob pattern %q (group %s): %v", glob, c.group, err)
+	}
 	if ok {
 		return true
 	}
 
 	ok, err = path.Match(glob, c.name)
+	if err != nil {
+		log.Warnf("invalid glob pattern %q (name %s): %v", glob, c.name, err)
+	}
 	if ok {
 		return true
 	}
@@ -652,7 +658,7 @@ func (g *Gatherer) poller() {
 			g.ticker = nil
 			close(doneCh)
 			return
-		case _ = <-g.ticker.C:
+		case <-g.ticker.C:
 			g.Poll()
 		}
 	}
@@ -668,7 +674,7 @@ func (g *Gatherer) Stop() {
 
 	doneCh := make(chan struct{})
 	g.stopCh <- doneCh
-	_ = <-doneCh
+	<-doneCh
 
 	g.stopCh = nil
 }
diff --git a/pkg/metrics/metrics_test.go b/pkg/metrics/metrics_test.go
index cc39fdc0b..2558411b8 100644
--- a/pkg/metrics/metrics_test.go
+++ b/pkg/metrics/metrics_test.go
@@ -17,6 +17,7 @@ package metrics_test
 import (
 	"bufio"
 	"context"
+	"fmt"
 	"net/http"
 	"strings"
 	"testing"
@@ -350,7 +351,6 @@ func (c collected) GetValue(name string) string {
 
 type testServer struct {
 	srv *http.Server
-	mux *http.ServeMux
 	r   *metrics.Registry
 	g   *metrics.Gatherer
 }
@@ -389,7 +389,10 @@ func newTestServer(t *testing.T, r *metrics.Registry, enabled, polled []string,
 
 func (srv *testServer) stop() {
 	if srv.srv != nil {
-		srv.srv.Shutdown(context.Background())
+		err := srv.srv.Shutdown(context.Background())
+		if err != nil && err != http.ErrServerClosed {
+			fmt.Printf("test server shutdown failed: %v\n", err)
+		}
 	}
 	if srv.g != nil {
 		srv.g.Stop()
@@ -422,7 +425,3 @@ func (srv *testServer) collect(t *testing.T) (described, collected) {
 
 	return described(types), collected(metrics)
 }
-
-func (srv *testServer) poll() {
-	srv.r.Poll()
-}