Add Token and RegularToken fields to TestServerSetup for pre-authenticated
access. Update setupTestServer to create fresh users with valid tokens at
initialization time. Simplify createTestMediaItemID to use setup.Token.
Remove loginTestUser, loginRegularUser, loginAdminUser functions in favor
of setup.Token/setup.RegularToken. Update createTestUserOnce and
getTestUserID/getRegularUserID to be idempotent. Update all test files to
use setup.Token instead of calling login helpers.
Removed unit tests that couldn't work without a database (nil db would
panic). Added comprehensive integration tests for the PreviewCollection
endpoint covering:
- Authentication (no auth, valid auth)
- Input validation (missing/invalid library ID, invalid JSON)
- Manual book selection
- Rule-based filtering
- Limit parameter handling
- Duplicate and invalid book ID handling
john-okeefe