Applied comments from I5d2166f155e31900cb40c to improve on
the unit test. makeMagicWordFactory() makes passing "null"
optional (which is default, hence some cleanup for calls).
Change-Id: Ib9a096c519f0de7286aa244bf3bb842cc11740f9
* testGetContentLanguage() - covers the getContentLanguage() method.
* testGet() - covers the get() method in the MagicWordFactory class.
* testGetVariableIDs() - covers the getVariableIDs method.
* testGetSubstIDs() - covers the getSubstIDs() method.
* testGetCacheTTL() - covers the getCacheTTL() method. This covers
both paths when there is a valid and an invalid caching hint.
* makeMagicWordFactory() - a helper function for creating an object
of the MagicWordFactory class.
* testGetDoubleUnderscoreArray() - covers getDoubleUnderscoreArray()
method and also calls newArray() under the hood so that is also
covered.
Change-Id: I5d2166f155e31900cb40c22fb976e81d0d545627
