Thank you for sharing this example! You've perfectly captured one of my main frustrations: pytest tries to be "helpful" by adding extra context, but ends up obscuring the actual error.
from vedro import scenario, asserts as _
@scenario
def calculate_discount():
product = ...
discounted = apply_discount(product, 0.2)
_.assert_equal(discounted.price, 80.0) assert error_code not in [400, 500]
# vs
assert_that(error_code, is_not(any_of(400, 500))) # hamcrest
3. I like that there's nothing new to learn, the expressions work exactly like they do in any Python code, with no special test behavior or surprises.