[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 26 matching lines @@
 
     prev_ignore = os.environ.pop(requests_ssl.ENV_VAR_IGNORE, '0')
     os.environ[requests_ssl.ENV_VAR_IGNORE] = '1'
     os.environ['RANDOM_MULTILINE_ENV'] = 'foo\nbar\nbaz\n'
     try:
       return (
           ['python', script_path] + eng_args + ['run', recipe] + proplist)
     finally:
       os.environ[requests_ssl.ENV_VAR_IGNORE] = prev_ignore
 
-  def _test_recipe(self, recipe, properties=None):
+  def _test_recipe(self, recipe, properties=None, env=None):
     proc = subprocess.Popen(
         self._run_cmd(recipe, properties),
         stdout=subprocess.PIPE,
-        stderr=subprocess.STDOUT)
+        stderr=subprocess.STDOUT,
+        env=env)
     stdout = proc.communicate()
     self.assertEqual(0, proc.returncode, '%d != %d when testing %s:\n%s' % (
         0, proc.returncode, recipe, stdout))
 
   def test_examples(self):
+    env = os.environ.copy()
+
+    # Set the "RECIPE_ENGINE_CONTEXT_TEST" environment variable to a known
+    # value, "default". This is used by the "context:tests/env" recipe module
+    # as a basis for runtime tests.
+    env['RECIPE_ENGINE_CONTEXT_TEST'] = 'default'
+
     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}],
       ['engine_tests/functools_partial'],
     ]
     for test in tests:
-      self._test_recipe(*test)
+      self._test_recipe(*test, env=env)
 
   def test_bad_subprocess(self):
     now = time.time()
     self._test_recipe('engine_tests/bad_subprocess')
     after = time.time()
 
     # Test has a daemon that holds on to stdout for 30s, but the daemon's parent
     # process (e.g. the one that recipe engine actually runs) quits immediately.
     # If this takes longer than 5 seconds to run, we consider it failed.
     self.assertLess(after - now, 5)
@@ skipping 178 matching lines @@
             u'foo',
             u'bar',
             u'baz',
           ],
         })
 
 
 if __name__ == '__main__':
   unittest.TestCase.maxDiff = None
   unittest.main()