Utilizes assertIsNone and assertIsNotNone - tests/api

Using assertTrue and the 'is None' operator to test if an element is None
is too python2.4. Our unit testing framework 'testtools' supports
assertIsNone and assertIsNotNone, included from python 2.7,
which were created for these types of tests.

Change-Id: I09f38e219931e0d7ad27f04861d1ebbc3b5e2c5f
Merge "Utilizes assertIsNone and assertIsNotNone - tests/api"