[autotest] Make rpc_interface_unittest to use django test

The rpc_interface_unittest avoided importing rpc_utils as they need
Django to be set up, otherwise the import would fail. To do that
it contained a lot of code for mocks.

This simplifies this by using the Django unittests.

TEST=Ran suites.
DEPLOY=afe,apache

Change-Id: I63d4b9f2f098b7e10ff5520dcae217da7147cc62
Reviewed-on: https://chromium-review.googlesource.com/212508
Reviewed-by: Alex Miller <milleral@chromium.org>
Tested-by: Jakob Jülich <jakobjuelich@chromium.org>
Commit-Queue: Jakob Jülich <jakobjuelich@chromium.org>
diff --git a/frontend/afe/site_rpc_interface.py b/frontend/afe/site_rpc_interface.py
index cb6a4f7..fa6cb15 100644
--- a/frontend/afe/site_rpc_interface.py
+++ b/frontend/afe/site_rpc_interface.py
@@ -17,6 +17,7 @@
 from autotest_lib.client.common_lib import global_config
 from autotest_lib.client.common_lib import priorities
 from autotest_lib.client.common_lib.cros import dev_server
+from autotest_lib.frontend.afe import rpc_utils
 from autotest_lib.server import utils
 from autotest_lib.server.cros.dynamic_suite import constants
 from autotest_lib.server.cros.dynamic_suite import control_file_getter
@@ -32,19 +33,6 @@
 # Relevant CrosDynamicSuiteExceptions are defined in client/common_lib/error.py.
 
 
-def _rpc_utils():
-    """Returns the rpc_utils module.  MUST be mocked for unit tests.
-
-    rpc_utils initializes django, which we can't do in unit tests.
-    This layer of indirection allows us to only load that module if we're
-    not running unit tests.
-
-    @return: autotest_lib.frontend.afe.rpc_utils
-    """
-    from autotest_lib.frontend.afe import rpc_utils
-    return rpc_utils
-
-
 def canonicalize_suite_name(suite_name):
     return 'test_suites/control.%s' % suite_name
 
@@ -192,7 +180,7 @@
 
     control_file = tools.inject_vars(inject_dict, control_file)
 
-    return _rpc_utils().create_job_common(name,
+    return rpc_utils.create_job_common(name,
                                           priority=priority,
                                           timeout_mins=timeout_mins,
                                           max_runtime_mins=timeout*60,
@@ -224,7 +212,7 @@
     config_values = {}
     for section in sections:
         config_values[section] = _CONFIG.config.items(section)
-    return _rpc_utils().prepare_for_serialization(config_values)
+    return rpc_utils.prepare_for_serialization(config_values)
 
 
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