diff --git a/test/helpers/invariants.hpp b/test/helpers/invariants.hpp
index abb8fb1e..fec7ee65 100644
--- a/test/helpers/invariants.hpp
+++ b/test/helpers/invariants.hpp
@@ -82,16 +82,39 @@ namespace test
             }
         };
 
-        // Finally, check that size matches up.
+        // Check that size matches up.
+
         if(x1.size() != size) {
             BOOST_ERROR("x1.size() doesn't match actual size.");
             std::cout<<x1.size()<<"/"<<size<<std::endl;
         }
+
+        // Check the load factor.
+
         float load_factor =
             static_cast<float>(size) / static_cast<float>(x1.bucket_count());
         using namespace std;
         if(fabs(x1.load_factor() - load_factor) > x1.load_factor() / 64)
             BOOST_ERROR("x1.load_factor() doesn't match actual load_factor.");
+
+        // Check that size in the buckets matches up.
+
+        BOOST_DEDUCED_TYPENAME X::size_type bucket_size = 0;
+
+        for (BOOST_DEDUCED_TYPENAME X::size_type
+                i = 0; i < x1.bucket_count(); ++i)
+        {
+            for (BOOST_DEDUCED_TYPENAME X::const_local_iterator
+                    begin = x1.begin(i), end = x1.end(i); begin != end; ++begin)
+            {
+                ++bucket_size;
+            }
+        }
+
+        if(x1.size() != bucket_size) {
+            BOOST_ERROR("x1.size() doesn't match bucket size.");
+            std::cout<<x1.size()<<"/"<<bucket_size<<std::endl;
+        }
     }
 }