1 files changed, 14 insertions, 3 deletions
diff --git a/src/pkg/net/interface_test.go b/src/pkg/net/interface_test.go
index e31894abf..efabb5f3c 100644
--- a/src/pkg/net/interface_test.go
+++ b/src/pkg/net/interface_test.go
@@ -108,12 +108,23 @@ func testInterfaceMulticastAddrs(t *testing.T, ifi *Interface) {
 func testAddrs(t *testing.T, ifat []Addr) {
 	for _, ifa := range ifat {
 		switch ifa := ifa.(type) {
-		case *IPAddr, *IPNet:
-			if ifa == nil {
-				t.Errorf("\tunexpected value: %v", ifa)
+		case *IPAddr:
+			if ifa == nil || ifa.IP == nil {
+				t.Errorf("\tunexpected value: %v, %v", ifa, ifa.IP)
 			} else {
 				t.Logf("\tinterface address %q", ifa.String())
 			}
+		case *IPNet:
+			if ifa == nil || ifa.IP == nil || ifa.Mask == nil {
+				t.Errorf("\tunexpected value: %v, %v, %v", ifa, ifa.IP, ifa.Mask)
+			} else {
+				_, prefixLen := ifa.Mask.Size()
+				if ifa.IP.To4() != nil && prefixLen != 8*IPv4len || ifa.IP.To16() != nil && ifa.IP.To4() == nil && prefixLen != 8*IPv6len {
+					t.Errorf("\tunexpected value: %v, %v, %v, %v", ifa, ifa.IP, ifa.Mask, prefixLen)
+				} else {
+					t.Logf("\tinterface address %q", ifa.String())
+				}
+			}
 		default:
 			t.Errorf("\tunexpected type: %T", ifa)
 		}