diff --git a/src/sync_mixin.cc b/src/sync_mixin.cc
index 4a5c48f..0e8f2c5 100644
--- a/src/sync_mixin.cc
+++ b/src/sync_mixin.cc
@@ -68,14 +68,12 @@ namespace pEp {
 #endif
 
         jmp_buf SyncMixIn::env;
-        int SyncMixIn::val;
         void *SyncMixIn::_msg;
 
         int SyncMixIn::inject_sync_msg(void *msg, void *management)
         {
-            val = 0;
             _msg = msg;
-            setjmp(env);
+            int val = setjmp(env);
             if (!val)
                 do_sync_protocol(session, management);
             return 0;
diff --git a/src/sync_mixin.hh b/src/sync_mixin.hh
index c9e43c2..41d71a5 100644
--- a/src/sync_mixin.hh
+++ b/src/sync_mixin.hh
@@ -29,7 +29,6 @@ namespace pEp {
                         pEp_identity *me, pEp_identity *partner);
 
                 static jmp_buf env;
-                static int val;
                 static void *_msg;
                 static int inject_sync_msg(void *msg, void *management);
                 static void *retrieve_next_sync_msg(void *management);
diff --git a/test/sync_test.py b/test/sync_test.py
index 6467f84..7f71a50 100644
--- a/test/sync_test.py
+++ b/test/sync_test.py
@@ -19,5 +19,12 @@ class Handler(SyncMixIn):
 
 handler = Handler()
 
+
+def process(path):
+    with open(path, 'r') as f:
+        text = f.read()
+    return Message(text)
+
+
 # this is an interactive test, so start it with python -i