How to mock a list of objects by side_effecting its attribute-CodePudding

I want to unittest the following function which takes a list of RunInfo objects as argument.

def get_mses(runs):
    mse = []
    for r in runs:  
        metrics = mlflow.get_run(r.run_id).data.metrics
        mse.append(metrics['cv_mse'])
    
    return mse

While the main logic is around metrics, it does need to iterate the runs and grab the attribute run_id to retrieve information about each run. However I don't think I need to mock the actual RunInfo class, but rather some fake class with an attribute run_id. How do I mock this and create a list of objects by specifying the run_ids as simple as (1, 2, 3) using side_effects?

I found this post, but it is not exactly what I am trying to do.

CodePudding user response：

You shouldn't have to use side_effects for this purpose. unittest.mock has a NonCallableMock class that can hold arbitrary attributes.

from unittest import mock

runs = [mock.NonCallableMock(run_id=i) for i in range(1,4)]