Open and close buffer cache before and after inverted indexes test cases.
diff --git a/hyracks/hyracks-tests/hyracks-storage-am-lsm-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/common/LSMInvertedIndexTestHarness.java b/hyracks/hyracks-tests/hyracks-storage-am-lsm-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/common/LSMInvertedIndexTestHarness.java
index 99087f0..3293ab4 100644
--- a/hyracks/hyracks-tests/hyracks-storage-am-lsm-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/common/LSMInvertedIndexTestHarness.java
+++ b/hyracks/hyracks-tests/hyracks-storage-am-lsm-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/common/LSMInvertedIndexTestHarness.java
@@ -107,6 +107,7 @@
             IVirtualBufferCache virtualBufferCache = new VirtualBufferCache(new HeapBufferAllocator(), memPageSize,
                     memNumPages / numMutableComponents);
             virtualBufferCaches.add(virtualBufferCache);
+            virtualBufferCache.open();
         }
         rnd.setSeed(RANDOM_SEED);
         invIndexFileRef = ioManager.getIODevices().get(0).createFileReference(onDiskDir + invIndexFileName);
@@ -129,6 +130,9 @@
             }
         }
         dir.delete();
+        for (int i = 0; i < numMutableComponents; i++) {
+            virtualBufferCaches.get(i).close();
+        }
     }
 
     public FileReference getInvListsFileRef() {