Ensure parent id added only when we need an identifier for the child

test/run.sh

 #!/bin/bash
 # Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 # Usage: call directly in the commandline as test/run.sh ensuring that you have
 # both 'dart' and 'DumpRenderTree' in your path. Filter tests by passing a
 # pattern as an argument to this script.
 
 # TODO(sigmund): replace with a real test runner
 
 # bail on error
 set -e
 
 # print commands executed by this script
 # set -x
 
 DIR=$( cd $( dirname "${BASH_SOURCE[0]}" ) && pwd )
 DART_FLAGS="--checked"
 TEST_PATTERN=$1
 
 function show_diff {
-  echo -en "Expected"
-  echo -n "                                                           "
-  echo -e "Output"
-  diff -t -y $1 $2 | \
-    sed -e "s/\(^.\{63\}\)\(\s[<]\(\s\|$\)\)\(.*\)/\1\2\4/" |\
-    sed -e "s/\(^.\{63\}\)\(\s[|]\(\s\|$\)\)\(.*\)/\1\2\4/" |\
-    sed -e "s/\(^.\{63\}\)\(\s[>]\(\s\|$\)\)\(.*\)/\1\2\4/"
+  diff -u $1 $2 | \
+    sed -e "s/^\(+.*\)/\x1b[32m\1\x1b[0m/" |\
+    sed -e "s/^\(-.*\)/\x1b[31m\1\x1b[0m/"
   return 1
 }
 
 function update {
   read -p "Would you like to update the expectations? [y/N]: " answer
   if [[ $answer == 'y' || $answer == 'Y' ]]; then
     cp $2 $1
     return 0
   fi
   return 1
@@ skipping 60 matching lines @@
 # Run Dart analyzer to check that we're generating warning clean code.
 OUT_PATTERN="$DIR/data/output/*$TEST_PATTERN*_bootstrap.dart"
 if [[ `ls $OUT_PATTERN 2>/dev/null` != "" ]]; then
   echo -e "\n Analyzing generated code for warnings or type errors."
   # TODO(jmesserly): batch mode does not return the right exit code.
   ls $OUT_PATTERN | dart_analyzer --fatal-warnings --fatal-type-errors \
     --work $DIR/data/output/analyzer/ -batch
 fi
 
 echo All tests pass.