make it easier to mock instance events for sensor tests

[sryza]

Use Case

The best way right now to test an asset sensor required mock.patch:

@mock.patch("dagster.core.instance.DagsterInstance.events_for_asset_key")
def test_first_events(mock_events_for_asset_key):
    mock_events_for_asset_key.side_effect = get_mock_events_for_asset_key(
        [("comments", 1), ("stories", 2)]
    )

    with tempfile.TemporaryDirectory() as tmpdir_path:
        context = SensorExecutionContext(
            instance_ref=InstanceRef.from_dir(tmpdir_path),
            last_run_key=None,
            last_completion_time=None,
        )
        requests = story_recommender_sensor.get_execution_data(context)
        assert len(requests) == 1
        assert requests[0].run_key == "1|2"

Ideas of Implementation

create_sensor_context(instance=instance_with_events(events))

Additional Info

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Message from the maintainers:

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