Help with plugin assertion rewriting #5931
Description
Hey, I was looking at the pytest-clarity package and it does something really nice, imo, which is it turns this:
into:
The downside is that the rewriting results in a loss of functionality:
a = [1, 2, 3]
b = [1, 2]
def test_a():
assert len(a) == len(b)Goes from
def test_a():
> assert len(a) == len(b)
E assert 3 == 2
E + where 3 = len([1, 2, 3])
E + and 2 = len([1, 2])
to
def test_a():
> assert len(a) == len(b)
E assert left == right failed.
E Showing split diff:
E
E left: 3
E right: 2
I've been digging through the source and I can't quite find the right part to use to do this. It stems from use of pytest_assertrepr_compare but I can't find anything in pytest I can use to construct that 3 = len([1, 2, 3]). I'm looking for some pointers if anyone can help put me on the right track. I was barking down the AssertionRewriter which I think is what I'm looking for but I can't quite put my finger on how to modify these assertions in way that still utilizes that code.