diff --git a/helpers/metric.go b/helpers/metric.go
index 1f7e34e..9a7c454 100644
--- a/helpers/metric.go
+++ b/helpers/metric.go
@@ -47,6 +47,10 @@ type Metric struct {
 	Value  float64
 }
 
+func (m *Metric) String() string {
+	return fmt.Sprintf("%+v", *m)
+}
+
 // Less returns true if m < m2 in some stable order. Can be used for sorting.
 func (m *Metric) Less(m2 *Metric) bool {
 	if m.Name != m2.Name {
diff --git a/helpers/metric_test.go b/helpers/metric_test.go
index 811d35a..257f68d 100644
--- a/helpers/metric_test.go
+++ b/helpers/metric_test.go
@@ -128,4 +128,8 @@ func TestLess(t *testing.T) {
 	if !reflect.DeepEqual(expected, actual) {
 		t.Errorf("Less:\nexpected = %+v\actual = %+v", expected, actual)
 	}
+
+	if s := expected[0].String(); s != "{Name:counter Help:metric description Labels:map[instance:test1 job:test] Type:COUNTER Value:36.6}" {
+		t.Errorf("Unexpected String(): %q for %#v", s, expected[0])
+	}
 }