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Mock Google Pub/Sub publish and pull in Python
A lightweight in-memory mock of Google Pub/Sub with publisher/subscriber classes to test topic-based fan-out and message pulling without real infrastructure.
import json
import time
from collections import deque
from dataclasses import dataclass, field
from typing import Any, Callable
@dataclass
class Message:
data: str
attributes: dict[str, str] = field(default_factory=dict)
message_id: str | None = None
ack_id: str | None = None
class MockPublisher:
…How to Mock NATS Subject Hierarchies with Wildcards in Python
Build a lightweight NATS-style pub/sub mock that matches subject hierarchies with '*' and '>' wildcards for tests or prototypes.
# Mock a simplified NATS subject hierarchy with wildcard matching
# Supports: exact match, '*' (single token), '>' (tail wildcard)
class NATSSubjectMock:
def __init__(self):
self.subscriptions = {} # subject -> list of callbacks
def subscribe(self, subject, callback):
self.subscriptions.setd…In-Memory PubSub Topic Subscribe Mock in Python
Build a thread-safe in-memory publish/subscribe mock where handlers subscribe to named topics and receive every message published to them.
class PubSub:
def __init__(self):
self.topics = {}
def subscribe(self, topic, callback):
if topic not in self.topics:
self.topics[topic] = []
self.topics[topic].append(callback)
def publish(self, topic, message):
for callback in self.topics.get(topic, []):
…How to Mock Redis Pub/Sub in Python
Test Redis pub/sub logic without a live server using an in-memory fake that queues published messages per channel.
import redis
import time
import threading
class MockRedisPubSub:
def __init__(self):
self.channels = {}
def publish(self, channel, message):
if channel not in self.channels:
return 0
for subscriber in self.channels[channel]:
subscriber.put(message)
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