Add test for net dev stats

container/libcontainer/helpers.go

@@ -171,11 +171,11 @@ func scanInterfaceStats(netStatsFile string) ([]info.InterfaceStats, error) {
 
 		i := info.InterfaceStats{}
 
-		numRead, _ := fmt.Sscanf(line, netstatsLine,
+		_, err := fmt.Sscanf(line, netstatsLine,
 			&i.Name, &i.RxBytes, &i.RxPackets, &i.RxErrors, &i.RxDropped, &bkt, &bkt, &bkt,
 			&bkt, &i.TxBytes, &i.TxPackets, &i.TxErrors, &i.TxDropped, &bkt, &bkt, &bkt, &bkt)
 
-		if numRead == 17 && !isIgnoredDevice(i.Name) {
+		if err == nil && !isIgnoredDevice(i.Name) {
 			stats = append(stats, i)
 		}
 	}

container/libcontainer/helpers_test.go

@@ -0,0 +1,63 @@
+// Copyright 2014 Google Inc. All Rights Reserved.
+//
+// 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 libcontainer
+
+import (
+	"testing"
+
+	info "github.com/google/cadvisor/info/v1"
+)
+
+func TestScanInterfaceStats(t *testing.T) {
+	stats, err := scanInterfaceStats("testdata/procnetdev")
+	if err != nil {
+		t.Error(err)
+	}
+
+	var netdevstats = []info.InterfaceStats{
+		{
+			Name:      "wlp4s0",
+			RxBytes:   1,
+			RxPackets: 2,
+			RxErrors:  3,
+			RxDropped: 4,
+			TxBytes:   9,
+			TxPackets: 10,
+			TxErrors:  11,
+			TxDropped: 12,
+		},
+		{
+			Name:      "em1",
+			RxBytes:   315849,
+			RxPackets: 1172,
+			RxErrors:  0,
+			RxDropped: 0,
+			TxBytes:   315850,
+			TxPackets: 1173,
+			TxErrors:  0,
+			TxDropped: 0,
+		},
+	}
+
+	if len(stats) != len(netdevstats) {
+		t.Errorf("Expected 2 net stats, got %d", len(stats))
+	}
+
+	for i, v := range netdevstats {
+		if v != stats[i] {
+			t.Errorf("Expected %#v, got %#v", v, stats[i])
+		}
+	}
+}

container/libcontainer/testdata/procnetdev

@@ -0,0 +1,6 @@
+Inter-|   Receive                                                |  Transmit
+ face |bytes    packets errs drop fifo frame compressed multicast|bytes    packets errs drop fifo colls carrier compressed
+wlp4s0:       1       2    3    4    5     6          7         8        9       10    11    12    13     14       15          0
+docker0:       0       0    0    0    0     0          0         0        0       0    0    0    0     0       0          0
+    lo:  0    0    0    0    0     0          0         0   0    0    0    0    0     0       0          0
+   em1:  315849    1172    0    0    0     0          0         0   315850    1173    0    0    0     0       0          0