Utilizes assertIn - tests/api/etc

Using assertTrue and the 'in' operator to test
if an element is in a sequence is too python2.4.
Our unit testing framework supports assertIn,
which was created for these types of tests.
Adapting assertIn will enhance the readability of the test scripts.

Change-Id: I9995c6668710e94902d97da21303274965df17e9
Merge "Utilizes assertIn - tests/api/etc"