Replace real world datasets with fake in the tests
It would be better for unit tests to remove the dependency on external datasets, and use fake datasets instead.

For e2e tests, we could have both:
- fake datasets, but hosted on the hub
- real datasets
Replace real world datasets with fake in the tests: It would be better for unit tests to remove the dependency on external datasets, and use fake datasets instead.

For e2e tests, we could have both:
- fake datasets, but hosted on the hub
- real datasets