[loader] Make recipe engine support examples/ module subdir

recipe_modules/path/example.py

-# 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.
-
-DEPS = [
-  'path',
-  'platform',
-  'properties',
-  'step',
-]
-
-from recipe_engine.config_types import Path
-
-def RunSteps(api):
-  api.step('step1', ['/bin/echo', str(api.path['tmp_base'].join('foo'))])
-
-  # module.resource(...) demo.
-  api.step('print resource',
-           ['echo', api.path.resource('dir', 'file.py')])
-
-  # module.package_repo_resource() demo.
-  api.step('print package dir',
-           ['echo', api.path.package_repo_resource('dir', 'file.py')])
-
-  assert 'checkout' not in api.path
-  api.path['checkout'] = api.path['tmp_base'].join('checkout')
-  assert 'checkout' in api.path
-
-  # Global dynamic paths (see config.py example for declaration):
-  dynamic_path = api.path['checkout'].join('jerky')
-  api.step('checkout path', ['/bin/echo', dynamic_path])
-
-  # Methods from python os.path are available via api.path.
-  # For testing, we asserted that this file existed in the test description
-  # below.
-  assert api.path.exists(api.path['tmp_base'])
-
-  temp_dir = api.path.mkdtemp('kawaab')
-  assert api.path.exists(temp_dir)
-
-  file_path = api.path['tmp_base'].join('new_file')
-  abspath = api.path.abspath(file_path)
-  api.path.assert_absolute(abspath)
-
-  api.step('touch me', ['touch', api.path.abspath(file_path)])
-  # Assert for testing that a file exists.
-  api.path.mock_add_paths(file_path)
-  assert api.path.exists(file_path)
-
-  realpath = api.path.realpath(file_path)
-  assert api.path.exists(realpath)
-
-  home_path = api.path.join(api.path.expanduser('~'), 'file')
-  api.step('touch my home', ['touch', home_path])
-  api.path.mock_add_paths(home_path)
-  assert api.path.exists(home_path)
-
-  # Convert strings to Paths
-  paths_to_convert =  [
-    api.path['start_dir'].join('some', 'thing'),
-    api.path['start_dir'],
-    api.path.resource("module_resource.py"),
-    api.path.resource(),
-    api.resource("recipe_resource.py"),
-    api.resource(),
-  ]
-  for p in paths_to_convert:
-    after = api.path.abs_to_path(str(p))
-    api.step('converted path %s' % p, ['echo', after])
-    assert after == p, (after, p)
-
-  try:
-    api.path.abs_to_path('non/../absolute')
-    assert False, "this should have thrown"  # pragma: no cover
-  except ValueError as ex:
-    assert "is not absolute" in ex.message, ex
-
-  try:
-    if api.platform.is_win:
-      api.path.abs_to_path('C:\some\other\root\non\absolute')
-    else:
-      api.path.abs_to_path('/some/other/root/non/absolute')
-    assert False, "this should have thrown"  # pragma: no cover
-  except ValueError as ex:
-    assert "could not figure out" in ex.message, ex
-
-
-def GenTests(api):
-  for platform in ('linux', 'win', 'mac'):
-    yield (api.test(platform) + api.platform.name(platform) +
-           # Test when a file already exists
-           api.path.exists(api.path['tmp_base']))
-
-    # We have support for chromium swarming built in to the engine for some
-    # reason. TODO(phajdan.jr) remove it.
-    yield (api.test('%s_swarming' % platform) +
-           api.platform.name(platform) +
-           api.properties(path_config='swarming') +
-           api.path.exists(api.path['tmp_base']))
-
-    yield (api.test('%s_kitchen' % platform) +
-           api.platform.name(platform) +
-           api.properties(path_config='kitchen') +
-           api.path.exists(api.path['tmp_base']))
-
-    yield (api.test('%s_luci' % platform) +
-           api.platform.name(platform) +
-           api.properties(**{
-              '$recipe_engine/path': {
-                'cache_dir': '/c',
-                'temp_dir': '/t'
-              },
-           }) +
-           api.path.exists(api.path['tmp_base']))