Fix SliceTest

Author: Sylvain Lebresne

src/java/org/apache/cassandra/db/Slices.java

@@ -193,6 +193,7 @@ public Builder add(Slice.Bound start, Slice.Bound end)
         public Builder add(Slice slice)
         {
             assert slices.size() == 0 || comparator.compare(slices.get(slices.size()-1).end(), slice.start()) <= 0;
+            assert comparator.compare(slice.start(), slice.end()) <= 0;
             slices.add(slice);
             return this;
         }

test/unit/org/apache/cassandra/db/filter/SliceTest.java

@@ -365,11 +365,11 @@ public void testValidateSlices()
         assertSlicesValid(cc, slices(s(3, 3), s(4, 4)));
         assertSlicesValid(cc, slices(s(0, 3), s(4, 5), s(6, 9)));
         assertSlicesValid(cc, slices(s(-1, -1)));
-        assertSlicesValid(cc, slices(s(-1, 3), s(4, -1)));
 
         assertSlicesInvalid(cc, slices(s(0, 2), s(2, 4)));
         assertSlicesInvalid(cc, slices(s(0, 2), s(1, 4)));
         assertSlicesInvalid(cc, slices(s(0, 2), s(3, 4), s(3, 4)));
+        assertSlicesInvalid(cc, slices(s(-1, 3), s(4, -1)));
         assertSlicesInvalid(cc, slices(s(-1, 2), s(3, -1), s(5, 9)));
     }