In case of error, pipe something in

This lets me run tests in a terminal.  If I mess up and the terminal is
being read by `cat` or similar, this input is used instead and now my
tests will automatically fail properly.

run-tests

@@ -9,7 +9,7 @@ for TEST in tests/*.expected; do
     BASE="${TEST%.expected}"
 
     echo -n "$BASE ... "
-    (
+    echo "Do not read this input" | (
         . "${BASE}.env"
         . ./mo "${BASE}.template"
     ) | diff -wU5 - "${TEST}" > "${BASE}.diff"