fix little bugs in the tests

tests/TestNaveau2015.cpp

@@ -693,5 +693,5 @@ int main(int argc, char *argv[])
   {
     std::cerr << msg << std::endl;
   }
-  return 1;
+  return 0;
 }

tests/TestObject.cpp

@@ -237,6 +237,7 @@ namespace PatternGeneratorJRL
       if (! srdf_stream.is_open())
       {
         const std::string exception_message (filename + " does not seem to be a valid file.");
+        cerr << exception_message << endl ;
         throw std::invalid_argument(exception_message);
       }
       // Read xml stream

tests/TestOptCholesky.cpp

@@ -181,5 +181,14 @@ int main()
   delete anOptCholesky;
   delete [] L;
   delete [] A;
+
+  if (return_value == -1){
+    cout << "Failed test" << endl;
+  }
+  else
+  {
+    cout << "Passed test" << endl;
+  }
+
   return return_value;
 }