Whenever possible (i.e. when your test does not mutate datasets), you should use the default bucket available at BigQueryTestCase::$bucket. If you must create a dataset, use BigQueryTestCase::createDataset() in order to correctly configure the deletion queue.

Because datasets cannot be deleted unless they are empty, it is sometimes difficult to ensure that deletion is queued in the correct order. Due to this, tables should NOT be added to the deletion queue. Instead, they should be created inside a dataset which was created using BigQueryTestCase::createDataset().

When the deletion queue is processed, all datasets created using the BigQueryTestCase::createDataset() method will be deleted with the deleteContents flag set to override the deletion protections in the service.