image_test: Split into the lib, and the tests

image_test module imports some third party modules. In order for us to
not depend on them at bootstrap time, this CL reorganizes those imports
into an image_test_lib module, and keep only the tests in image_test
module.

BUG=brillo:1158
TEST=unittests
TEST=trybots on release groups

Change-Id: Ia60e74414abf49e8f9f81fbabd28b19d59a0cadf
Reviewed-on: https://chromium-review.googlesource.com/274447
Commit-Queue: Nam Nguyen <namnguyen@chromium.org>
Tested-by: Nam Nguyen <namnguyen@chromium.org>
Trybot-Ready: Nam Nguyen <namnguyen@chromium.org>
Reviewed-by: David James <davidjames@chromium.org>
diff --git a/scripts/test_image.py b/scripts/test_image.py
index 12ac501..23b8eb9 100644
--- a/scripts/test_image.py
+++ b/scripts/test_image.py
@@ -12,7 +12,7 @@
 from chromite.cbuildbot import constants
 from chromite.lib import commandline
 from chromite.lib import cros_logging as logging
-from chromite.lib import image_test
+from chromite.lib import image_test_lib
 from chromite.lib import osutils
 from chromite.lib import path_util
 
@@ -62,13 +62,13 @@
 
   # Build up test suites.
   loader = unittest.TestLoader()
-  loader.suiteClass = image_test.ImageTestSuite
+  loader.suiteClass = image_test_lib.ImageTestSuite
   # We use a different prefix here so that unittest DO NOT pick up the
   # image tests automatically because they depend on a proper environment.
   loader.testMethodPrefix = 'Test'
-  all_tests = loader.loadTestsFromName('chromite.lib.image_test')
-  forgiving = image_test.ImageTestSuite()
-  non_forgiving = image_test.ImageTestSuite()
+  all_tests = loader.loadTestsFromName('chromite.cros.test.image_test')
+  forgiving = image_test_lib.ImageTestSuite()
+  non_forgiving = image_test_lib.ImageTestSuite()
   for suite in all_tests:
     for test in suite.GetTests():
       if test.IsForgiving():
@@ -77,7 +77,7 @@
         non_forgiving.addTest(test)
 
   # Run them in the image directory.
-  runner = image_test.ImageTestRunner()
+  runner = image_test_lib.ImageTestRunner()
   runner.SetBoard(opts.board)
   runner.SetResultDir(opts.test_results_root)
   image_file = FindImage(opts.image_dir)