Address comments

staging/src/k8s.io/component-base/metrics/testutil/metrics.go

@@ -262,10 +262,6 @@ func validateMetricFamily(gatherer metrics.Gatherer, metricName string) (*dto.Me
 		}
 	}
 
-	if metricFamily == nil {
-		return nil, fmt.Errorf("metric %q not found", metricName)
-	}
-
 	if metricFamily.GetMetric() == nil {
 		return nil, fmt.Errorf("metric %q is empty", metricName)
 	}
@@ -278,7 +274,7 @@ func validateMetricFamily(gatherer metrics.Gatherer, metricName string) (*dto.Me
 
 // GetHistogramVecFromGatherer collects a metric, that matches the input labelValue map
 // from a gatherer implementing k8s.io/component-base/metrics.Gatherer interface.
-// All metrics within the metricFamily will be assembled as a single HistogramVec. Quantle, Average etc. are caculated based on
+// All metrics within the metricFamily will be assembled as a single HistogramVec. Quantile, Average etc. are caculated based on
 // the accumulated data from the HistogramVec.
 // Used only for testing purposes where we need to gather metrics directly from a running binary (without metrics endpoint).
 func GetHistogramVecFromGatherer(gatherer metrics.Gatherer, metricName string, lvMap map[string]string) (HistogramVec, error) {
@@ -303,10 +299,10 @@ type LabeledHistogram struct {
 	Histogram Histogram
 }
 
-// GetHistogramFromGatherer collects a metric from a gatherer implementing k8s.io/component-base/metrics.Gatherer interface.
+// GetHistogramsFromGatherer collects a metric from a gatherer implementing k8s.io/component-base/metrics.Gatherer interface.
 // If the metric is a HistogramVec, each metric from the HistogramVec will be collected with a label map one by one.
 // Used only for testing purposes where we need to gather metrics directly from a running binary (without metrics endpoint).
-func GetHistogramFromGatherer(gatherer metrics.Gatherer, metricName string, lvMap map[string]string) ([]LabeledHistogram, error) {
+func GetHistogramsFromGatherer(gatherer metrics.Gatherer, metricName string, lvMap map[string]string) ([]LabeledHistogram, error) {
 	metricFamily, err := validateMetricFamily(gatherer, metricName)
 	if err != nil {
 		return nil, err

staging/src/k8s.io/component-base/metrics/testutil/metrics_test.go

@@ -22,8 +22,12 @@ import (
 	"reflect"
 	"testing"
 
+	"k8s.io/component-base/metrics"
+	"k8s.io/component-base/metrics/legacyregistry"
 	"k8s.io/utils/pointer"
 
+	"github.com/google/go-cmp/cmp"
+	"github.com/prometheus/client_golang/prometheus"
 	dto "github.com/prometheus/client_model/go"
 )
 
@@ -512,3 +516,38 @@ func TestHistogramVec_Validate(t *testing.T) {
 		})
 	}
 }
+
+func TestGetHistogramFromGatherer(t *testing.T) {
+	// Have multiple labels defined here, but we only care about the first label, i.e. "extension_point".
+	labels := []string{"extension_point", "status"}
+	lvMap := map[string]string{"extension_point": "*"}
+	HistogramOpts := &metrics.HistogramOpts{
+		Namespace: "namespace",
+		Name:      "metric_test_name",
+		Subsystem: "subsystem",
+		Help:      "histogram help message",
+		Buckets:   prometheus.DefBuckets,
+	}
+	vec := metrics.NewHistogramVec(HistogramOpts, labels)
+	legacyregistry.MustRegister(vec)
+	vec.WithLabelValues("filter", "0").Observe(1.5)
+	vec.WithLabelValues("score", "0").Observe(3.5)
+	metricName := fmt.Sprintf("%s_%s_%s", HistogramOpts.Namespace, HistogramOpts.Subsystem, HistogramOpts.Name)
+	histogramList, err := GetHistogramsFromGatherer(legacyregistry.DefaultGatherer, metricName, lvMap)
+	if err != nil {
+		t.Errorf("Got error %v", err)
+	}
+	expectedList := []LabeledHistogram{
+		{
+			Labels:    map[string]string{"extension_point": "filter"},
+			Histogram: samples2Histogram([]float64{1.5}, prometheus.DefBuckets),
+		},
+		{
+			Labels:    map[string]string{"extension_point": "score"},
+			Histogram: samples2Histogram([]float64{3.5}, prometheus.DefBuckets),
+		},
+	}
+	if diff := cmp.Diff(histogramList, expectedList); diff != "" {
+		t.Errorf("Got unexpected histogramList:\n%s", diff)
+	}
+}

test/integration/scheduler_perf/util.go

@@ -256,7 +256,7 @@ func collectHistogramVec(metric string, labels map[string]string, lvMap map[stri
 
 func collectHistogram(metric string, labels map[string]string, lvMap map[string]string) []DataItem {
 	var dataItems []DataItem
-	vec, err := testutil.GetHistogramFromGatherer(legacyregistry.DefaultGatherer, metric, lvMap)
+	vec, err := testutil.GetHistogramsFromGatherer(legacyregistry.DefaultGatherer, metric, lvMap)
 	if err != nil {
 		klog.Error(err)
 		return nil