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.
Get user from request and put in authz attribs.

Added integration tests for user-based auth.