diff --git a/tests/mklargefile.py b/tests/mklargefile.py
new file mode 100644
index 0000000..6261c65
--- /dev/null
+++ b/tests/mklargefile.py
@@ -0,0 +1,12 @@
+#! /usr/bin/python
+import sys
+
+if __name__ == '__main__':
+   if len(sys.argv)<3:
+       print sys.argv[0],'<filename> <filesize (in GB)>'
+   else:
+       GB=1024*1024*1024
+       f=open(sys.argv[1],'w')
+       f.seek(long(sys.argv[2])*GB)
+       f.write('!')
+       f.close();