Nik

add support for conditional top-level DDL statements

5

This adds support for conditional statements for most top-level DDL statements. I skipped a few statements that look like internals or ones that IMO don't need this: 1. `CREATE/DROP DATABASE`...

Support pytest verbs test-system (was: Unable to rollback transactions using pytest and in_transaction context manager)

7

**Describe the bug** I wrote a pytest fixture that should be automatically run for each test. This fixture starts a new transaction using the `in_transaction` context manager, yields, and then...