cp "$file1" "$testname.$basename1"
cp "$file2" "$testname.$basename2"
test_failure_ "$(diff -u "$testname.$basename1" "$testname.$basename2")"
cp "$file1" "$testname.$basename1"
cp "$file2" "$testname.$basename2"
test_failure_ "$(diff -u "$testname.$basename1" "$testname.$basename2")"