blueprint relocation-test-codes
The current test file structure in horizon looks random.
This is the first patch of blueprint relocation-test-codes.
This commit proposes to change the structure to match the structure
of test targets (i.e., main codes).
More concretely, a unit test file for {TOP_MODULE}/{MODULE}/{FILENAME}.py
will be located at {TOP_MODULE}/test/units/{MODULE}/test_{FILENAME}.py.
When a module is test as a whole, a location of a corresponding test file
will be {TOP_MODULE}/test/units/{MODULE}/test_{MODULE}.py.
This clarifies locations of test files.
In addition, this commit changes the base class of utils.test_secret_key
from horizon.test.helper.TestCase to unittest.TestCase. This is because
calling secret_key.generate_key() somehow interferes django.test.TestCase
(which is a parent class of horizon.test.helper.TestCase).
Change-Id: I48b9c317645e63a5819c52512b30f25969574817