--- /tmp/test-driver	2018-09-18 15:06:54.000000000 +0200
+++ /usr/share/automake-1.16/test-driver	2019-05-16 17:58:09.690988983 +0200
@@ -104,7 +104,8 @@ trap "st=141; $do_exit" 13
 trap "st=143; $do_exit" 15
 
 # Test script is run here.
-"$@" >$log_file 2>&1
+echo -n "" >"$log_file"
+"$@" >>"$log_file" 2>&1
 estatus=$?
 
 if test $enable_hard_errors = no && test $estatus -eq 99; then