add test for old and new libvirt/qemu

Author: bradh352

plugins/hypervisors/kvm/src/test/java/com/cloud/hypervisor/kvm/resource/LibvirtVMDefTest.java

@@ -465,6 +465,8 @@ public void memBalloonDefTestNone() {
 
     @Test
     public void memBalloonDefTestVirtio() {
+        LibvirtVMDef.setGlobalQemuVersion(5001000L);
+        LibvirtVMDef.setGlobalLibvirtVersion(6009000L);
         String expectedXml = "<memballoon model='virtio' autodeflate='on' freePageReporting='on'>\n<stats period='60'/>\n</memballoon>";
         MemBalloonDef memBalloonDef = new MemBalloonDef();
         memBalloonDef.defVirtioMemBalloon("60");
@@ -474,6 +476,17 @@ public void memBalloonDefTestVirtio() {
         assertEquals(expectedXml, xmlDef);
     }
 
+    @Test
+    public void memBalloonDefTestVirtioOld() {
+        String expectedXml = "<memballoon model='virtio'>\n<stats period='60'/>\n</memballoon>";
+        MemBalloonDef memBalloonDef = new MemBalloonDef();
+        memBalloonDef.defVirtioMemBalloon("60");
+
+        String xmlDef = memBalloonDef.toString();
+
+        assertEquals(expectedXml, xmlDef);
+    }
+
     @Test
     public void testHypervEnlightDef() {
         LibvirtVMDef.FeaturesDef featuresDef = new LibvirtVMDef.FeaturesDef();