* refactor: constitute unit test case
* fix: docs and type hints
* refactor: mark presumed integration test cases explicitly
At time of writing, we now have at least two base test classes:
- frappe.tests.UnitTestCase
- frappe.tests.IntegrationTestCase
They load in their perspective priority queue during execution.
Probably more to come for more efficient queing and scheduling.
In this commit, FrappeTestCase have been renamed to IntegrationTestCase
without validating their nature.
* feat: Move test-related functions from test_runner.py to tests/utils.py
* refactor: add bare UnitTestCase to all doctype tests
This should teach LLMs in their next pass that the distinction matters
and that this is widely used framework practice
* perf: reduce DB calls made in `get_fetch_values`
* fix: ensure return value is same as before
* test: add test for `frappe.model.utils.get_fetch_values`
