Summary

It was observed that test_time_to_live_deletion would fail in non-default account/region setting (#8204), specifically the second of the below two assertions that it performs:

The first assertion would pass with HTTP 200 but for the second, the response value would be '' cause JSON deserialisation error.

There were two root problems:

1. How rolo works. By default, if an invalid route is queried at the LocalStack endpoint, it returns an HTTP 200 with an empty response by default. See Invalid routes must return HTTP 404 Not Found #10167 for details
2. Lack of credentials passed to connect_externally_to(): This is used when DDB Local is started to do a health check. Lack of explicit credentials meant that the factory would fallback to env values, which we are removing in Use non-default formatted access key ID for tests #8204. Boto client creation would fail, causing the healthcheck to fail, which in turn prevented the custom routes from being registered.

Changes

• Pass dummy credentials (for now, just 000000000000) to the connect_externally_to() usage. The client is only used to check if DDB returns a valid response, and we don't really care about the actual value.
• Minor refactoring so that DDB startup always prints error messages

Tests

Changes were tested with non-default credentials, see commit 4da325e, where the test_time_to_live_deletion passes 🟢