Added support for dual-homed hosts (on "classic" topo).

Change-Id: I47f4b3bf5756928452cbf99c4be2e3e1d6c8fa92
diff --git a/tools/test/topos/dual.json b/tools/test/topos/dual.json
new file mode 100644
index 0000000..fa86e0e
--- /dev/null
+++ b/tools/test/topos/dual.json
@@ -0,0 +1,21 @@
+{
+  "devices": {
+    "of:0000000000000001": { "basic": { "name": "SW-A" }},
+    "of:0000000000000002": { "basic": { "name": "SW-B" }}
+  },
+
+  "hosts": {
+    "00:00:00:00:00:01/-1": {
+      "basic": {
+        "locations": [
+          "of:0000000000000001/1",
+          "of:0000000000000002/1"
+        ],
+        "ips": [
+          "10.0.0.1"
+        ],
+        "name": "Host-X"
+      }
+    }
+  }
+}