diff --git a/callback_dispatcher.cc b/callback_dispatcher.cc
index da1e209..3b82872 100644
--- a/callback_dispatcher.cc
+++ b/callback_dispatcher.cc
@@ -100,9 +100,8 @@ namespace pEp {
             PEP_STATUS status = PassphraseCache::messageToSend(passphrase_cache, Adapter::session());
 
             // if the cache has no valid passphrase ask the app
-            if (status == PEP_PASSPHRASE_REQUIRED || status == PEP_WRONG_PASSPHRASE) {
+            if (status == PEP_PASSPHRASE_REQUIRED || status == PEP_WRONG_PASSPHRASE)
                 semaphore.stop();
-            }
 
             // the pEp engine must try again
             return status;
diff --git a/test/Makefile b/test/Makefile
index 574f0be..63a19d4 100644
--- a/test/Makefile
+++ b/test/Makefile
@@ -6,7 +6,7 @@ CXXFLAGS+=-I../
 
 .PHONY=all, test_adapter, test_adapter_cxx, test_library
 
-all: test_adapter test_adapter_cxx test_library test_passphrase_cache
+all: test_adapter test_adapter_cxx test_library test_passphrase_cache test_semaphore
 
 test_adapter: test_adapter.cc ../libpEpAdapter.a
 
@@ -16,6 +16,8 @@ test_library: test_library.cc ../libpEpAdapter.a
 
 test_passphrase_cache: test_passphrase_cache.cc ../libpEpAdapter.a
 
+test_semaphore: test_semaphore.cc ../libpEpAdapter.a
+
 clean:	
 	rm -vf test_adapter
 	rm -rvf test_adapter.dSYM
diff --git a/test/test_semaphore.cc b/test/test_semaphore.cc
new file mode 100644
index 0000000..29c3889
--- /dev/null
+++ b/test/test_semaphore.cc
@@ -0,0 +1,35 @@
+#include <iostream>
+#include <thread>
+#include <unistd.h>
+#include "Semaphore.hh"
+
+using namespace std;
+using namespace pEp;
+
+int main()
+{
+    Semaphore semaphore;
+
+    thread thread1([&](){
+            cout << "1: before stop\n";
+            semaphore.stop();
+            cout << "1: now on stop\n";
+            semaphore.try_wait();
+            cout << "1: and on go again\n";
+            semaphore.try_wait();
+            cout << "1: keeping going\n";
+        });
+
+    sleep(1);
+
+    thread thread2([&](){
+            cout << "2: setting go\n";
+            semaphore.go();
+        });
+
+    thread1.join();
+    thread2.join();
+
+    return 0;
+}
+