Assert more conditions in authentication tests, prep for JGit test

There is still an open problem in the fetch_() test case for JGit.
It does not checkout the files, so the assertion for the existence
of the expected README.md file fails.  

That assertion is temporarily disabled.  It will be enabled once
the issue is understood and resolved.
Add JGit credentials test
Merge commit '3c70f4cbaca38d3396a91bea313d2a05ceada34f' into HEAD