Originally, you repeatedly referred to an error; now you seem to have changed that to a warning

Sorry for the confusion.

My module throws warnings and errors - it generates both by printing to STDERR

The question wasn't so much about dealing with warnings and errors but more about suppressing the warnings during the output from the tests. Although, this is one of those situations where I didn't really know exactly what I wanted to know until I had asked the question and got lots of helpful comments. The original question asked about suppressing this line 

Stripe Webhook Error: Invalid Stripe Signature

[download]
Hence why I referred to errors

In reply to Re^4: STDERR in Test Results by Bod
in thread STDERR in Test Results by Bod

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