Documentation of "how-to-do-testing"

[LauJohansson]

We could make a short example of how to do testing of a ETL flow using the TestHandle.

from atc_tools.testing.TestHandle import TestHandle
from atc.utils import DataframeCreator

test_schema =  ...
test_columns = ...
test_data = ...
expected_data = ...

params = BusinessETLParameters()

params.source_dh =  TestHandle(
            provides=DataframeCreator.make_partial(
                test_schema , 
                test_columns,
                 test_data 
            )
        )

params.target_dh =  TestHandle(
            provides=DataframeCreator.make_partial(
                test_schema , 
                test_columns,
                 test_data 
            )
        )

orchestrator= BusinessETLOrchestrator(params)

orchestrator.execute()

self.assertDataframeMatches(params.target.overwritten, None, expected_data )