Update tests to have custom routes

Docker-DCO-1.1-Signed-off-by: Guillaume J. Charmes <guillaume.charmes@docker.com> (github: creack)
Upstream-commit: b1d26985d0dfcbecc8264124fa81ff843a6d574b
Component: engine

components/engine/networkdriver/network.go

@@ -12,6 +12,10 @@ var (
 	ErrNetworkOverlaps                = errors.New("requested network overlaps with existing network")
 )
 
+var (
+	networkGetRoutesFct = netlink.NetworkGetRoutes
+)
+
 func CheckNameserverOverlaps(nameservers []string, toCheck *net.IPNet) error {
 	if len(nameservers) > 0 {
 		for _, ns := range nameservers {
@@ -28,7 +32,7 @@ func CheckNameserverOverlaps(nameservers []string, toCheck *net.IPNet) error {
 }
 
 func CheckRouteOverlaps(toCheck *net.IPNet) error {
-	networks, err := netlink.NetworkGetRoutes()
+	networks, err := networkGetRoutesFct()
 	if err != nil {
 		return err
 	}

components/engine/networkdriver/network_test.go

@@ -35,12 +35,19 @@ func TestOverlapingNameservers(t *testing.T) {
 }
 
 func TestCheckRouteOverlaps(t *testing.T) {
-	routesData := []string{"10.0.2.0/32", "10.0.3.0/24", "10.0.42.0/24", "172.16.42.0/24", "192.168.142.0/24"}
+	orig := networkGetRoutesFct
+	defer func() {
+		networkGetRoutesFct = orig
+	}()
+	networkGetRoutesFct = func() ([]netlink.Route, error) {
+		routesData := []string{"10.0.2.0/32", "10.0.3.0/24", "10.0.42.0/24", "172.16.42.0/24", "192.168.142.0/24"}
 
-	routes := []netlink.Route{}
-	for _, addr := range routesData {
-		_, netX, _ := net.ParseCIDR(addr)
-		routes = append(routes, netlink.Route{IPNet: netX})
+		routes := []netlink.Route{}
+		for _, addr := range routesData {
+			_, netX, _ := net.ParseCIDR(addr)
+			routes = append(routes, netlink.Route{IPNet: netX})
+		}
+		return routes, nil
 	}
 
 	_, netX, _ := net.ParseCIDR("172.16.0.1/24")