diff --git a/tests/junit-functional/org/jgroups/tests/BufferTest.java b/tests/junit-functional/org/jgroups/tests/BufferTest.java
index 238d7e1497..856206a684 100644
--- a/tests/junit-functional/org/jgroups/tests/BufferTest.java
+++ b/tests/junit-functional/org/jgroups/tests/BufferTest.java
@@ -36,8 +36,8 @@ public class BufferTest {
     @DataProvider
     static Object[][] windowCreator() {
         return new Object[][]{
-          //{new DynamicBuffer<>(0)},
-           {new FixedBuffer<>(0)}
+          {new DynamicBuffer<>(0)},
+          {new FixedBuffer<>(0)}
         };
     }
 
@@ -476,8 +476,13 @@ public void testAddAndRemove(Buffer<Message> buf) {
         buf.add(5, msg(5, true), dont_loopback_filter, Options.DEFAULT());
         buf.add(6, msg(6, true), dont_loopback_filter, Options.DEFAULT());
         assert buf.highestDelivered() == 6;
-        for(int i=0; i <= 6; i++)
-            assert buf._get(i) == null;
+        if(buf instanceof FixedBuffer)
+            for(int i=1; i <= 6; i++)
+                assert buf._get(i) == null;
+        else {
+            assert IntStream.rangeClosed(1,2).boxed().allMatch(n -> buf._get(n) == null);
+            assert IntStream.rangeClosed(3,6).boxed().allMatch(n -> buf._get(n) != null);
+        }
     }
 
     public void testAddAndRemove2(Buffer<Message> buf) {