[context] Split "env" values and prefixes.

recipe_engine/unittests/run_test.py

 #!/usr/bin/env python
 # Copyright 2014 The LUCI Authors. All rights reserved.
 # Use of this source code is governed under the Apache License, Version 2.0
 # that can be found in the LICENSE file.
 
 import json
 import os
 import re
 import subprocess
 import unittest
@@ skipping 37 matching lines @@
     proc = subprocess.Popen(
         self._run_cmd(recipe, properties),
         stdout=subprocess.PIPE,
         stderr=subprocess.STDOUT)
     stdout = proc.communicate()
     self.assertEqual(0, proc.returncode, '%d != %d when testing %s:\n%s' % (
         0, proc.returncode, recipe, stdout))
 
   def test_examples(self):
     tests = [
+      ['context:examples/full'],
+      ['context:tests/env'],
       ['step:examples/full'],
       ['path:examples/full'],
       ['raw_io:examples/full'],
       ['python:examples/full'],
       ['json:examples/full'],
       ['uuid:examples/full'],
       ['file:examples/copy'],
       ['file:examples/copytree'],
 
       ['engine_tests/depend_on/top', {'to_pass': 42}],
@@ skipping 192 matching lines @@
             u'foo',
             u'bar',
             u'baz',
           ],
         })
 
 
 if __name__ == '__main__':
   unittest.TestCase.maxDiff = None
   unittest.main()