diff --git a/test/TestRunner.sh b/test/TestRunner.sh
index bb20728..5555364 100755
--- a/test/TestRunner.sh
+++ b/test/TestRunner.sh
@@ -18,6 +18,9 @@
 SUBST=$1
 FILEDIR=`dirname $TESTNAME`
 
+# Make diagnostic printing more determinstic.
+export COLUMNS=999
+
 OUTPUT=Output/$1.out
 
 # create the output directory if it does not already exist