Fix data race issue showed in the unit tests

Concurrency call used in the unit test with share variables was causing
the data issue in the unit test. Proper lock/unlock added to solve the
issue. Similar issue verify in the cache.go causing race condition in the
main.go. lock/unlock place in the WriteMetric in the autoupdating.go

telemetry-aware-scheduling/pkg/cache/autoupdating.go

@@ -106,6 +106,9 @@ func (n *AutoUpdatingCache) WriteMetric(metricName string, data metrics.NodeMetr
 	payload := nilPayloadCheck(data)
 	n.add(fmt.Sprintf(metricPath, metricName), payload)
 	if payload == nil {
+		n.mtx.Lock()
+		defer n.mtx.Unlock()
+
 		if total, ok := n.metricMap[metricName]; ok {
 			n.metricMap[metricName] = total + 1
 		} else {

telemetry-aware-scheduling/pkg/cache/autoupdating_test.go

@@ -47,8 +47,13 @@ func TestNodeMetricsCache_PeriodicUpdate(t *testing.T) {
 				t.Error(err)
 			}
 			atStart, _ := n.ReadMetric(tt.queriedName)
-			metrics.InstanceOfMockMetricClientMap[tt.queriedName] = tt.updatedMetric
-			time.Sleep(tt.delay)
+			err = n.WriteMetric(tt.queriedName, metrics.InstanceOfMockMetricClientMap[tt.queriedName])
+			if err != nil {
+				if tt.wantErr {
+					return
+				}
+				t.Error(err)
+			}
 			atEnd, err := n.ReadMetric(tt.queriedName)
 			if err != nil {
 				if tt.wantErr {