Remove BackupLastSuccessfulTimestampCount, use Metrics() in test

Remove the exported method that was only used in tests. Use the
existing Metrics() getter to access the gauge directly in the
backup controller test instead.

Signed-off-by: Shubham Pampattiwar <spampatt@redhat.com>

pkg/controller/backup_controller_test.go

@@ -31,6 +31,7 @@ import (
 	"github.com/google/go-cmp/cmp"
 	"github.com/google/go-cmp/cmp/cmpopts"
 	snapshotv1api "github.com/kubernetes-csi/external-snapshotter/client/v8/apis/volumesnapshot/v1"
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/sirupsen/logrus"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/mock"
@@ -2049,10 +2050,11 @@ func Test_updateTotalBackupMetric_prunesStaleTimestamps(t *testing.T) {
 	require.NoError(t, err)
 
 	m := metrics.NewServerMetrics()
+	gauge := m.Metrics()["backup_last_successful_timestamp"].(*prometheus.GaugeVec)
 
 	// Simulate a previous resync that set the metric for "deleted-schedule"
 	m.SetBackupLastSuccessfulTimestamp("deleted-schedule", baseTime)
-	require.Equal(t, 1, m.BackupLastSuccessfulTimestampCount())
+	require.Equal(t, 1, collectGaugeCount(t, gauge))
 
 	// Current backups only contain entries for "active-schedule"
 	backups := []velerov1api.Backup{
@@ -2070,7 +2072,19 @@ func Test_updateTotalBackupMetric_prunesStaleTimestamps(t *testing.T) {
 	}
 
 	// Only "active-schedule" should remain; "deleted-schedule" should be pruned
-	assert.Equal(t, 1, m.BackupLastSuccessfulTimestampCount())
+	assert.Equal(t, 1, collectGaugeCount(t, gauge))
+}
+
+func collectGaugeCount(t *testing.T, g *prometheus.GaugeVec) int {
+	t.Helper()
+	ch := make(chan prometheus.Metric, 10)
+	g.Collect(ch)
+	close(ch)
+	count := 0
+	for range ch {
+		count++
+	}
+	return count
 }
 
 // Unit tests to make sure that the backup's status is updated correctly during reconcile.