Rewrite blink_gc_plugin test script in Python.

tools/clang/blink_gc_plugin/tests/test.sh

-#!/bin/bash
-#
-# Copyright 2014 The Chromium Authors. All rights reserved.
-# Use of this source code is governed by a BSD-style license that can be
-# found in the LICENSE file.
-#
-# Hacky, primitive testing: This runs the style plugin for a set of input files
-# and compares the output with golden result files.
-
-E_BADARGS=65
-E_FAILEDTEST=1
-
-failed_any_test=
-
-# Prints usage information.
-usage() {
-  echo "Usage: $(basename "${0}")" \
-    "<path to clang>" \
-    "<path to plugin>"
-  echo ""
-  echo "  Runs all the libBlinkGCPlugin unit tests"
-  echo ""
-}
-
-# Runs a single test case.
-do_testcase() {
-  local flags=""
-  if [ -e "${3}" ]; then
-    flags="$(cat "${3}")"
-  fi
-  local output="$("${CLANG_PATH}" -c -Wno-c++11-extensions \
-      -Wno-inaccessible-base \
-      -Xclang -load -Xclang "${PLUGIN_PATH}" \
-      -Xclang -add-plugin -Xclang blink-gc-plugin ${flags} ${1} 2>&1)"
-  local json="${input%cpp}graph.json"
-  if [ -f "$json" ]; then
-    output="$(python ../process-graph.py -c ${json} 2>&1)"
-  fi
-  local diffout="$(echo "${output}" | diff - "${2}")"
-  if [ "${diffout}" = "" ]; then
-    echo "PASS: ${1}"
-  else
-    failed_any_test=yes
-    echo "FAIL: ${1}"
-    echo "Output of compiler:"
-    echo "${output}"
-    echo "Expected output:"
-    cat "${2}"
-    echo
-  fi
-}
-
-# Validate input to the script.
-if [[ -z "${1}" ]]; then
-  usage
-  exit ${E_BADARGS}
-elif [[ -z "${2}" ]]; then
-  usage
-  exit ${E_BADARGS}
-elif [[ ! -x "${1}" ]]; then
-  echo "${1} is not an executable"
-  usage
-  exit ${E_BADARGS}
-elif [[ ! -f "${2}" ]]; then
-  echo "${2} could not be found"
-  usage
-  exit ${E_BADARGS}
-else
-  export CLANG_PATH="${1}"
-  export PLUGIN_PATH="${2}"
-  echo "Using clang ${CLANG_PATH}..."
-  echo "Using plugin ${PLUGIN_PATH}..."
-
-  # The golden files assume that the cwd is this directory. To make the script
-  # work no matter what the cwd is, explicitly cd to there.
-  cd "$(dirname "${0}")"
-fi
-
-for input in *.cpp; do
-  do_testcase "${input}" "${input%cpp}txt" "${input%cpp}flags"
-done
-
-if [[ "${failed_any_test}" ]]; then
-  exit ${E_FAILEDTEST}
-fi