diff --git a/src/tests/json-rpc2-tests.lisp b/src/tests/json-rpc2-tests.lisp
index 0c4227e..e570c82 100644
--- a/src/tests/json-rpc2-tests.lisp
+++ b/src/tests/json-rpc2-tests.lisp
@@ -95,7 +95,7 @@
                     "{\"jsonrpc\":\"2.0\",\"method\":\"foobar\",\"id\":1}"
                     (strcat "{\"jsonrpc\":\"2.0\","
                             "\"error\":{\"code\":-32601,"
-                            "\"message\":\"Method not found: \\\"foobar\\\"\"},\"id\":1}")))
+                            "\"message\":\"Method not found: \\\"foobar\\\"\",\"data\":null},\"id\":1}")))
 
 (deftest test-invalid-json (json-rpc2-suite)
   (let* ((json-req  "{\"jsonrpc\": \"2.0\", \"method\": \"foobar, \"params\": \"bar\", \"baz]")
@@ -103,7 +103,7 @@
     (assert-true
         (string= json-resp
                  (strcat "{\"jsonrpc\":\"2.0\",\"error\":{\"code\":-32700,"
-                         "\"message\":\"Parse error\"},\"id\":null}")))))
+                         "\"message\":\"Parse error\",\"data\":null},\"id\":null}")))))
 
 (deftest test-invalid-request (json-rpc2-suite)
   (let* ((json-req  "{\"jsonrpc\": \"2.0\", \"method\": 1, \"params\": \"bar\"}")
@@ -111,7 +111,7 @@
     (assert-true
         (string= json-resp
                  (strcat "{\"jsonrpc\":\"2.0\",\"error\":"
-                         "{\"code\":-32600,\"message\":\"Invalid Request\"},\"id\":null}")))))
+                         "{\"code\":-32600,\"message\":\"Invalid Request\",\"data\":null},\"id\":null}")))))
 
 (deftest test-batch (json-rpc2-suite)
   (prepare-rpc
@@ -124,7 +124,7 @@
           (expected (strcat "["
                             "{\"jsonrpc\":\"2.0\",\"result\":30,\"id\":2},"
                             "{\"jsonrpc\":\"2.0\",\"error\":{\"code\":-32601,"
-                            "\"message\":\"Method not found: \\\"foo\\\"\"},\"id\":1},"
+                            "\"message\":\"Method not found: \\\"foo\\\"\",\"data\":null},\"id\":1},"
                             "{\"jsonrpc\":\"2.0\",\"result\":3,\"id\":1}"
                             "]")))
       (assert-equality #'string=
@@ -141,7 +141,7 @@
     (assert-true
         (string= json-resp
                  (strcat "{\"jsonrpc\":\"2.0\",\"error\":"
-                         "{\"code\":-32700,\"message\":\"Parse error\"},\"id\":null}")))))
+                         "{\"code\":-32700,\"message\":\"Parse error\",\"data\":null},\"id\":null}")))))
 
 (deftest test-batch-empty-array (json-rpc2-suite)
   (let* ((json-req "[]")
@@ -149,7 +149,7 @@
     (assert-true
         (string= json-resp
                  (strcat "{\"jsonrpc\":\"2.0\",\"error\":"
-                         "{\"code\":-32600,\"message\":\"Invalid Request\"},\"id\":null}")))))
+                         "{\"code\":-32600,\"message\":\"Invalid Request\",\"data\":null},\"id\":null}")))))
 
 (deftest test-batch-invalid (json-rpc2-suite)
   (let* ((json-req "[1]")
@@ -158,7 +158,7 @@
         (string= json-resp
                  (strcat "["
                          "{\"jsonrpc\":\"2.0\",\"error\":"
-                         "{\"code\":-32600,\"message\":\"Invalid Request\"},\"id\":null}"
+                         "{\"code\":-32600,\"message\":\"Invalid Request\",\"data\":null},\"id\":null}"
                          "]")))))
 
 (deftest test-batch-invalid-2 (json-rpc2-suite)
@@ -168,11 +168,11 @@
         (string= json-resp
                  (strcat "["
                          "{\"jsonrpc\":\"2.0\",\"error\":"
-                         "{\"code\":-32600,\"message\":\"Invalid Request\"},\"id\":null},"
+                         "{\"code\":-32600,\"message\":\"Invalid Request\",\"data\":null},\"id\":null},"
                          "{\"jsonrpc\":\"2.0\",\"error\":"
-                         "{\"code\":-32600,\"message\":\"Invalid Request\"},\"id\":null},"
+                         "{\"code\":-32600,\"message\":\"Invalid Request\",\"data\":null},\"id\":null},"
                          "{\"jsonrpc\":\"2.0\",\"error\":{\"code\":"
-                         "-32600,\"message\":\"Invalid Request\"},\"id\":null}"
+                         "-32600,\"message\":\"Invalid Request\",\"data\":null},\"id\":null}"
                          "]")))))
 
 (deftest test-batch-notification (json-rpc2-suite)