Remove strict name validation on assert.rejects statements

[PatStLouis]

I had occurrences where my server was returning a different type of error than what the test suite was expecting (ex: returning an HTTPException instead of an HTTPError) and marked the test as failed even if my server behaved correctly. I wonder if checking for a specific type of error is too strict of a validation here?

[BigBlueHat]

Seems OK to me. That was likely my fault as I was hoping to make it clear what types of errors we were expecting...but given the way APIs jump around, I think you're right and that specificity likely isn't important.