Add default network restart test case

Added restart test for default network so that we can test
bridge network persistence. Also added changes to dnet to
delete the default network if it is present.

Signed-off-by: Jana Radhakrishnan <mrjana@docker.com>

cmd/dnet/dnet.go

@@ -185,17 +185,22 @@ func createDefaultNetwork(c libnetwork.NetworkController) {
 		// Bridge driver is special due to legacy reasons
 		if d == "bridge" {
 			genericOption[netlabel.GenericData] = map[string]interface{}{
-				"BridgeName": nw,
+				"BridgeName":    "docker0",
+				"DefaultBridge": "true",
 			}
 			createOptions = append(createOptions,
 				libnetwork.NetworkOptionGeneric(genericOption),
 				ipamOption(nw))
 		}
 
-		if _, err := c.NetworkByName(nw); err == nil {
-			logrus.Debugf("Default network %s already present", nw)
-			return
+		if n, err := c.NetworkByName(nw); err == nil {
+			logrus.Debugf("Default network %s already present. Deleting it", nw)
+			if err = n.Delete(); err != nil {
+				logrus.Debugf("Network could not be deleted: %v", err)
+				return
+			}
 		}
+
 		_, err := c.NewNetwork(d, nw, createOptions...)
 		if err != nil {
 			logrus.Errorf("Error creating default network : %s : %v", nw, err)

test/integration/dnet/bridge.bats

@@ -49,6 +49,21 @@ function test_single_network_connectivity() {
     test_single_network_connectivity bridge 3
 }
 
+@test "Test default network dnet restart" {
+    skip_for_circleci
+
+    echo $(docker ps)
+
+    for iter in `seq 1 2`;
+    do
+	test_single_network_connectivity bridge 3
+	if [ "$iter" -eq 1 ]; then
+	    docker restart dnet-1-bridge
+	    sleep 5
+	fi
+    done
+}
+
 @test "Test bridge network" {
     skip_for_circleci
 
@@ -67,8 +82,10 @@ function test_single_network_connectivity() {
     for iter in `seq 1 2`;
     do
 	test_single_network_connectivity singlehost 3
-	docker restart dnet-1-bridge
-	sleep 2
+	if [ "$iter" -eq 1 ]; then
+	    docker restart dnet-1-bridge
+	    sleep 5
+	fi
     done
 
     dnet_cmd $(inst_id2port 1) network rm singlehost
@@ -84,12 +101,11 @@ function test_single_network_connectivity() {
     do
 	if [ "$iter" -eq 1 ]; then
 	    test_single_network_connectivity singlehost 3 skip
+	    docker restart dnet-1-bridge
+	    sleep 5
 	else
 	    test_single_network_connectivity singlehost 3
 	fi
-
-	docker restart dnet-1-bridge
-	sleep 5
     done
 
     dnet_cmd $(inst_id2port 1) network rm singlehost

test/integration/dnet/helpers.bash

@@ -110,7 +110,7 @@ EOF
 	   -v /usr/local/bin/runc:/usr/local/bin/runc \
 	   -w /go/src/github.com/docker/libnetwork \
 	   golang:1.4 ./cmd/dnet/dnet -d -D ${hopt} -c ${tomlfile}
-    sleep 2
+    sleep 3
 }
 
 function skip_for_circleci() {