refactor: add shared pubsub test fixtures and wait_for polling helper

[yashksaini-coder]

Summary

Introduces shared test infrastructure for the pubsub test suite restructuring (PR 1 of 6 per the plan in #378):

• tests/utils/pubsub/wait.py — wait_for() generic polling helper and wait_for_convergence() multi-node convergence helper, replacing inline definitions
• tests/core/pubsub/conftest.py — GossipSubHarness dataclass with .pubsubs, .hosts, .routers properties, plus gossipsub_nodes(), connected_gossipsub_nodes(), subscribed_mesh() context managers and a connected_gossipsub_pair fixture
• tests/core/pubsub/test_dummyaccount_demo.py — migrated to import wait_for_convergence from the shared module; removed 9 redundant @pytest.mark.trio decorators (covered by trio_mode = true in pyproject.toml)

This lays the foundation for subsequent PRs that will replace ~253 synchronization sleeps, standardize router extraction, flatten class-based tests, consolidate overlapping files, and tag slow tests.

Test plan

• All 9 tests in test_dummyaccount_demo.py pass
• All 395 pubsub tests collect successfully with the new conftest.py
• CI passes

Closes #378

cc @IronJam11 @seetadev

[Copilot]

Pull request overview

Adds shared pubsub test infrastructure to support the upcoming pubsub test suite refactor (per #378), centralizing synchronization helpers and common gossipsub fixtures/context managers.

Changes:

• Introduce tests/utils/pubsub/wait.py with reusable polling (wait_for) and multi-node convergence (wait_for_convergence) helpers.
• Add tests/core/pubsub/conftest.py with a GossipSubHarness wrapper plus context managers/fixtures for creating connected/subscribed gossipsub nodes.
• Refactor test_dummyaccount_demo.py to reuse the shared convergence helper and rely on global trio_mode = true instead of per-test @pytest.mark.trio.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
tests/utils/pubsub/wait.py	New shared polling/convergence utilities for pubsub test synchronization.
tests/core/pubsub/conftest.py	New shared harness + context managers/fixtures for creating connected/subscribed GossipSub test topologies.
tests/core/pubsub/test_dummyaccount_demo.py	Swaps inline convergence helper for shared import; removes redundant trio markers.

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[Copilot]

wait_for() determines async-ness via inspect.iscoroutinefunction(predicate), which misses common patterns like lambda: async_fn() or functools.partial(async_fn, ...). In those cases predicate() returns a coroutine object (truthy) and the helper will return immediately without awaiting it, potentially causing false positives and "coroutine was never awaited" warnings. Consider calling predicate() each loop and then await if the returned value is awaitable (e.g., inspect.isawaitable(result)), and update the type hint accordingly to avoid the type: ignore.

[Copilot]

connected_gossipsub_nodes() uses a fixed trio.sleep(0.1) after dense_connect(). This makes the fixture timing-dependent and can still be flaky (or unnecessarily slow) since pubsub peer registration is asynchronous; the codebase already has event-based helpers like Pubsub.wait_for_peer() intended to replace arbitrary sleeps. Suggest replacing the fixed sleep with a deterministic wait (e.g., wait until each pubsub observes at least one peer when n > 1, or otherwise expose a configurable settle/wait strategy) so the fixture actually guarantees “connected” semantics.

Suggested change

	async with gossipsub_nodes(n, **kwargs) as harness:
	await dense_connect(harness.hosts)
	await trio.sleep(0.1)
	peer_wait_timeout = kwargs.pop("peer_wait_timeout", 5.0)
	async with gossipsub_nodes(n, **kwargs) as harness:
	await dense_connect(harness.hosts)
	if n > 1:
	with trio.fail_after(peer_wait_timeout):
	for index, pubsub in enumerate(harness.pubsubs):
	target_host = harness.hosts[(index + 1) % n]
	await pubsub.wait_for_peer(target_host.get_id())