Tests depend on cratedb-toolkit, which depends on this package #320

This package and cratedb-toolkit depend on each other. The test suite gets its crate container from the toolkit's test helper (cratedb_toolkit.testing.testcontainers.cratedb.CrateDBTestAdapter), so .[test] installs cratedb-toolkit[testing], while the toolkit requires sqlalchemy-cratedb and imports insert_bulk and CrateDialect from it in util.database.

A change here can fail this whole suite before one test runs, and the fix would then wait on two releases. CI installs this checkout with pip install --editable=.[test], so the released toolkit imports sqlalchemy-cratedb from the checkout. Rename either of those two names and the toolkit's helper no longer loads, until a toolkit release adapts, and the toolkit cannot adapt until this package releases. A library the toolkit builds on should not run its tests on the toolkit.

The tests should start the container from testcontainers-python itself, which since version 4.15 ships a crate container class (testcontainers.community.cratedb.CrateDBContainer) that needs nothing from this ecosystem, and keep the few SQL helpers they use (an engine, run_sql, refresh_table, count_records) in a small class under tests/. crate/crash#502 does the same for crash; the two do not wait on each other.

Settled when .[test] no longer installs cratedb-toolkit and CI is green.