diff --git a/src/mtest.m b/src/mtest.m
index 6bc841de6cefb40af4d40dececba47294c9a54dd..703375ce6fa330026c91f7833bd7a31b16b4b905 100644
--- a/src/mtest.m
+++ b/src/mtest.m
@@ -85,6 +85,7 @@ for i=1:nn
     % Write the temporary test routine.
     tid = fopen([FNAME '_test_' int2str(i) '.m'],'w');
     fprintf(tid,['function [T,t,LOG] = ' FNAME '_test_' int2str(i) '()\n']);
+    fprintf(fid, '\nrng(1);\n\n');
     fprintf(tid,'try\n');
     if (length(file{b1(i)+1})>2 && isequal(file{b1(i)+1}(1:3), '%$ ')) || (length(file{b1(i)+1})>1 && isequal(file{b1(i)+1}(1:2), '%$'))
         remove_first_columns = true;