Enhancement: Split unit tests from integration tests, and leverage Testcontainers locally #5
Description
The current test suite expects a running ClickHouse instance, with the connection string passed in Environment Variables.
There is some confusion, as there is already ClickHouse.Client.IntegrationTests, but the unit test project also requires integration with a running instance. I take this to mean that integration refers here to integration with other libraries, where conventionally this is meant to differentiate from unit level testing.
This creates extra steps for local development, and leans on the CI process to run a full accounting.
One opportunity is to locally switch to Testcontainers, via https://testcontainers.com/modules/clickhouse/ to implement a zero-friction run of tests locally with a running Docker container.