CMSDK : Fix external view test

Java's assert doesn't really do much on android and just returns true, which
makes you feel good about your tests, but its just lying to you. On the long run
its best that you know the real result and fix it, hence switch to JUnit's assert.

CYNGNOS-3042

Change-Id: If7e5982b10abc1f842a52110973566818b1e3bf4