diff --git a/src/test/streams_tests.cpp b/src/test/streams_tests.cpp
index 1108dab58..6f71f71ab 100644
--- a/src/test/streams_tests.cpp
+++ b/src/test/streams_tests.cpp
@@ -80,14 +80,17 @@ BOOST_AUTO_TEST_CASE(streams_serializedata_xor)
 
     // Degenerate case
     
-    key += '\x00','\x00';
+    key += '\x00';
+    key += '\x00';
     ds.Xor(key);
     BOOST_CHECK_EQUAL(
             std::string(expected_xor.begin(), expected_xor.end()), 
             std::string(ds.begin(), ds.end()));
 
-    in += '\x0f','\xf0';
-    expected_xor += '\xf0','\x0f';
+    in += '\x0f';
+    in += '\xf0';
+    expected_xor += '\xf0';
+    expected_xor += '\x0f';
     
     // Single character key
 
@@ -105,14 +108,17 @@ BOOST_AUTO_TEST_CASE(streams_serializedata_xor)
 
     in.clear();
     expected_xor.clear();
-    in += '\xf0','\x0f';
-    expected_xor += '\x0f','\x00';
+    in += '\xf0';
+    in += '\x0f';
+    expected_xor += '\x0f';
+    expected_xor += '\x00';
                         
     ds.clear();
     ds.insert(ds.begin(), in.begin(), in.end());
 
     key.clear();
-    key += '\xff','\x0f';
+    key += '\xff';
+    key += '\x0f';
 
     ds.Xor(key);
     BOOST_CHECK_EQUAL(