Test Automation Frameworks and Tools Questions

import heapq
from typing import List, Tuple

def shard_tests(tests: List[Tuple[str, float]], N: int) -> List[List[str]]:
    """
    tests: list of (test_name, avg_seconds)
    N: number of workers/shards
    returns: list of N lists of test_names
    """
    if N <= 0:
        raise ValueError("N must be >= 1")
    # initialize shards: (current_total_time, shard_index)
    heap = [(0.0, i) for i in range(N)]
    heapq.heapify(heap)
    shards = [[] for _ in range(N)]

    # sort tests by descending estimated duration
    for name, dur in sorted(tests, key=lambda x: -x[1]):
        total, idx = heapq.heappop(heap)     # shard with smallest load
        shards[idx].append(name)
        heapq.heappush(heap, (total + float(dur), idx))

    return shards

# test_api_endpoint.py
def test_create_user_success(client, db_cleanup):  # fixtures for shared setup/teardown
    # Arrange
    payload = {"username": "alice", "email": "a@x.com"}
    headers = {"Authorization": "Bearer valid-token"}

    # Act
    resp = client.post("/api/users", json=payload, headers=headers)

    # Assert
    assert resp.status_code == 201
    assert resp.json()["username"] == "alice"
    assert db_user_exists("alice")  # helper verifying DB side-effect