grep for exact match when looking for test_helper

scripts/test

@@ -9,7 +9,7 @@ if [ $# -gt 0 ]; then # we have args
     # Remove trailing line numbers from filename, e.g. spec/my_spec.rb:33
     grep_filename=`echo $1 | sed 's/:.*$//g'`
 
-    (set +e; grep -r 'spec_helper' $grep_filename) > /dev/null
+    (set +e; grep -r '^spec_helper$' $grep_filename) > /dev/null
     if [ $? -eq 1 ]; then # no match; we have a stand-alone spec
         need_rails=''
     fi