Improve integration test

Use some constants for tokens.
Refactor tokenfile creation to function.
Reorder some test cases to make lookups follow creates so they succeed.
Add expected status code to test cases (some are not quite what expected,
so filed bugs #2112, #2113, #2114)
Check expected status codes.
Close Body after each iterations so that we don't run out of file handles
  when I add even more test cases in the next PR.
Handle that it is unpredictable whether status 200 or 202 is returned.
Merge pull request #2116 from erictune/improve_auth_integ

Improve integration test