--- /dev/null
+#!/bin/sh
+
+assert_eq () {
+ [ "$1" = "$2" ] || ( echo Assertion failed: "\"$1\"" = "\"$2\""; exit 1 )
+}
+
+assert_eq foo "$(echo foo | ./muddle)"
+assert_eq '(foo bar baz)' "$(echo '(foo bar baz)' | ./muddle)"
+assert_eq '(foo foo foo)' "$(echo '(foo foo foo)' | ./muddle)"