Add Snapshot Controller e2e metric tests

Signed-off-by: Grant Griffiths <ggriffiths@purestorage.com>

test/e2e/framework/metrics/snapshot_controller_metrics.go

@@ -0,0 +1,40 @@
+/*
+Copyright 2021 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package metrics
+
+import "k8s.io/component-base/metrics/testutil"
+
+// SnapshotControllerMetrics is metrics for controller manager
+type SnapshotControllerMetrics testutil.Metrics
+
+// Equal returns true if all metrics are the same as the arguments.
+func (m *SnapshotControllerMetrics) Equal(o SnapshotControllerMetrics) bool {
+	return (*testutil.Metrics)(m).Equal(testutil.Metrics(o))
+}
+
+func newSnapshotControllerMetrics() SnapshotControllerMetrics {
+	result := testutil.NewMetrics()
+	return SnapshotControllerMetrics(result)
+}
+
+func parseSnapshotControllerMetrics(data string) (SnapshotControllerMetrics, error) {
+	result := newSnapshotControllerMetrics()
+	if err := testutil.ParseMetrics(data, (*testutil.Metrics)(&result)); err != nil {
+		return SnapshotControllerMetrics{}, err
+	}
+	return result, nil
+}