Issue #166 exposed that the retry budget in _resolveDatabasePath() was too
small for slow Android devices, but no unit test exercised that code path.
Expose two testing helpers (resolveDatabasePathForTesting /
resetDatabasePathForTesting) and add two new tests using fake_async:
- verifies the retry loop eventually succeeds after transient failures
(a _SucceedAfterNPathProvider that fails N times then returns a path)
- verifies the function throws PlatformException with the right message
after exhausting all retries
Both tests advance fake time instead of waiting real-world milliseconds,
so they run in < 1 ms each.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
