def assert_validation_error(resp, field_name: str):
    assert resp.status_code == 422
    body = resp.json()
    assert body.get("success") is False
    assert body.get("error", {}).get("code") == "validation_error"
    # Ensure correlation id is present and echoed in header
    cid = body.get("correlation_id")
    assert isinstance(cid, str) and cid
    assert resp.headers.get("X-Correlation-ID") == cid
    # Ensure the field appears in details
    details = body.get("error", {}).get("details", [])
    assert any(field_name in ":".join(map(str, err.get("loc", []))) for err in details)


def assert_http_error(resp, status_code: int, message_substr: str):
    assert resp.status_code == status_code
    body = resp.json()
    assert body.get("success") is False
    assert body.get("error", {}).get("code") == "http_error"
    assert message_substr in body.get("error", {}).get("message", "")
    cid = body.get("correlation_id")
    assert isinstance(cid, str) and cid
    assert resp.headers.get("X-Correlation-ID") == cid