Improve test performance

[koletzilla]

Issue created to track changes we made to increase test times after the findings on https://github.com/ClickHouse/dbt-clickhouse/issues/499

Currently we have two types of test depending on where the CH cluster is located:

• test_matrix.yml: Uses a local CH cluster inside a docker-compose cluster. Currently we execute in parallel a matrix of tests with dimensions: CH version and Python version. One extra dimension is done serially in each execution: connection being done with HTTP or Native protocols. Total time per job is around 10 minutes. this is not an issue right now but any improvement would be welcome
• test_cloud.yml: Uses a CH cluster hosted in CH cloud. Currently these tests are not being used as we have found some problems that made these tests took too much time (>2h with a lot of flakyness):
  • The CH Cloud cluster was already overloaded.
  • The DBT test cannot be currently run in parallel against the same CH cloud instance as some test were colliding between them.

Pending improvements:

• Use a new CH Cloud cluster (we are working on it right now)
• Test a way to be able to execute the CH Cloud test in different clusters (also being worked)
• Be able to execute test in parallel: in progress, it will take time.