Add variable replacement in trace_inputs.py

tools/isolate/trace_inputs_test.py

 #!/usr/bin/env python
 # Copyright (c) 2012 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.
 
 import logging
 import os
 import unittest
 import sys
 
 FILE_NAME = os.path.abspath(__file__)
 ROOT_DIR = os.path.dirname(FILE_NAME)
 
 import trace_inputs
 
 
 class TraceInputs(unittest.TestCase):
   def test_process_quoted_arguments(self):
     test_cases = (
       ('"foo"', ['foo']),
       ('"foo", "bar"', ['foo', 'bar']),
       ('"foo"..., "bar"', ['foo', 'bar']),
       ('"foo", "bar"...', ['foo', 'bar']),
     )
     for actual, expected in test_cases:
       self.assertEquals(expected, trace_inputs.process_quoted_arguments(actual))
 
+  def test_variable_abs(self):
+    value = trace_inputs.Results.File(None, '/foo/bar', False)
+    actual = value.replace_variables({'$FOO': '/foo'})
+    self.assertEquals('$FOO/bar', actual.path)
+    self.assertEquals('$FOO/bar', actual.full_path)
+    self.assertEquals(True, actual.tainted)
+
+  def test_variable_rel(self):
+    value = trace_inputs.Results.File('/usr', 'foo/bar', False)
+    actual = value.replace_variables({'$FOO': 'foo'})
+    self.assertEquals('$FOO/bar', actual.path)
+    self.assertEquals(os.path.join('/usr', '$FOO/bar'), actual.full_path)
+    self.assertEquals(True, actual.tainted)
+
 
 def join_norm(*args):
   """Joins and normalizes path in a single step."""
   return unicode(os.path.normpath(os.path.join(*args)))
 
 
 if sys.platform != 'win32':
   class StraceInputs(unittest.TestCase):
     # Represents the root process pid (an arbitrary number).
     _ROOT_PID = 27
@@ skipping 251 matching lines @@
           'size': -1,
         },
       ]
       self._test_lines(lines, '/home/foo_bar_user/src', files)
 
 
 if __name__ == '__main__':
   VERBOSE = '-v' in sys.argv
   logging.basicConfig(level=logging.DEBUG if VERBOSE else logging.ERROR)
   unittest.main()