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How to Get Current Git Branch Name in Python with Mock Subprocess
Mocks the subprocess call to reliably test the current git branch name retrieval using GitPython.
import subprocess
from unittest.mock import patch, MagicMock
from git import Repo
import os
def get_current_branch(repo_path="."):
"""Get the current branch name of a git repository."""
repo = Repo(repo_path)
return repo.active_branch.name
if __name__ == "__main__":
# Mock subprocess to control the…How to Calculate Cloud Cost Estimates with a Python Dictionary
Mocks a cloud pricing calculator using a dictionary of service rates and computes total estimated cost for given service hours.
def estimate_cost(service, hours, rate_table=None):
if rate_table is None:
rate_table = {
"basic": 50,
"standard": 75,
"premium": 100
}
if service not in rate_table:
raise ValueError(f"Unknown service: {service}")
return rate_table[service] * hour…Build a Recipe Runner Mock in Python
A Python script that mocks a command runner recipe system: maps recipe names to shell commands, executes them with subprocess, and prints the output and exit code.
import subprocess
import sys
def run_recipe(recipe: str) -> None:
"""Simulate a command runner recipe by printing the command and exit code."""
print(f"Running recipe: {recipe}")
result = subprocess.run(recipe, shell=True, capture_output=True, text=True)
print(f"Exit code: {result.returncode}")
i…How to Test HTTPX Async Client Pool Reuse with Mocks in Python
Mock an httpx.AsyncClient to verify connection pool reuse by asserting GET calls share a single client instance across concurrent async requests.
import asyncio
import httpx
from unittest.mock import AsyncMock, patch, Mock
async def fetch_with_pool(client, url, n_reuses=3):
results = []
for i in range(n_reuses):
resp = await client.get(url)
results.append(resp.status_code)
await asyncio.sleep(0) # yield to loop to mimic real us…How to Benchmark Python Code with pytest-benchmark and mocks
Use pytest-benchmark to measure function performance while combining Mock and patch for controlled test scenarios.
import time
from unittest.mock import Mock, patch
import pytest
from pytest_benchmark.fixture import BenchmarkFixture
def heavy_operation(data: list[int]) -> int:
"""Simulates a CPU-bound operation."""
return sum(x * x for x in data)
def test_heavy_operation_benchmark(benchmark: BenchmarkFixture) -> None:…How to Run an Integration Test with Docker Compose Mock in Python
Run a Python integration test against a docker-compose environment, using mocks to simulate service health and business logic responses.
import subprocess
import json
from typing import Dict
def run_integration_test() -> Dict[str, str]:
"""
Simulates an integration test against a docker-compose environment
using a mock service that returns canned responses.
"""
# Mock docker-compose environment check
env_ready = subprocess.run(…How to Use Stubs, Fakes, Spies, and Mocks in Python Testing
Implement four types of test doubles — stubs, fakes, spies, and mocks — as subclasses of a PaymentGateway interface to replace real dependencies during testing.
class PaymentGateway:
def charge(self, amount):
raise NotImplementedError
class StubPaymentGateway(PaymentGateway):
"""Returns a fixed response without any logic."""
def charge(self, amount):
return {"success": True, "transaction_id": "stub-12345"}
class FakePaymentGateway(PaymentGatewa…How to Serialize a Dataclass to JSON in Python
Serialize a Python dataclass instance to JSON using asdict and json.dumps for API responses or mocks.
from dataclasses import dataclass, asdict
import json
@dataclass
class UserResponse:
id: int
name: str
email: str
active: bool = True
if __name__ == "__main__":
response = UserResponse(id=42, name="Ada Lovelace", email="ada@example.com")
print(json.dumps(asdict(response), indent=2))How to Mock Kafka Topic Partitions with a Python dict of lists
Mocks a Kafka topic and its partitions using a defaultdict of lists to simulate message production, consumption, and per-partition counts.
from collections import defaultdict
class KafkaTopicPartitionMock:
"""A simple mock for Kafka topic-partition assignment using dict of lists."""
def __init__(self, topic):
self.topic = topic
self.partitions = defaultdict(list) # partition_id -> list of messages
def produce(self, message…Simulate RabbitMQ QoS Prefetch Count in Python
Mocks RabbitMQ QoS prefetch semantics using threading and a queue to cap concurrent unacked message processing per worker.
import threading
import time
import queue
class RabbitMQMock:
def __init__(self, prefetch_count=1):
self.prefetch_count = prefetch_count
self.channel_queue = queue.Queue()
self.currently_processing = 0
self.lock = threading.Lock()
def start_consuming(self, messages, worker_co…How to Implement Namespaced Cache Keys for Tenant Isolation in Python
Build a tenant-aware cache wrapper that prefixes keys with tenant and namespace, and test it with mocks.
from keyvaluestore import SimpleCache
from unittest.mock import patch
class TenantCache(SimpleCache):
def __init__(self, tenant_id, namespace="default"):
super().__init__()
self.tenant_id = tenant_id
self.namespace = namespace
def _key(self, key):
return f"tenant:{self.tenant_…How to Serialize Cache Values with JSON and Pickle in Python
Serialize cache values using JSON for simple types or pickle for arbitrary objects, with robust error handling for unsupported types like mocks.
import json
import pickle
from unittest.mock import Mock
def serialize(value, method="json"):
"""Serialize a cache value using JSON or pickle with type checking."""
if method == "json":
try:
return json.dumps(value).encode("utf-8")
except TypeError as e:
raise ValueErro…How to create a stable cache key from function arguments in Python
Generate a stable SHA-256 cache key from normalized function arguments, with keyword order normalized and tests using mocks.
import hashlib
import json
from unittest.mock import Mock
def make_cache_key(*args, **kwargs):
"""Normalize args/kwargs into a stable hash key for caching."""
normalized = {
"args": [repr(arg) for arg in args],
"kwargs": {key: repr(value) for key, value in sorted(kwargs.items())}
}
pa…How to Mock a Schema Registry Avro Record in Python
Encode a Python dict into Avro binary using an inline schema, mimicking a schema registry record for tests or mocks.
import io
from avro.schema import parse
from avro.io import DatumWriter, BinaryEncoder
schema_json = """
{
"type": "record",
"name": "User",
"fields": [
{"name": "name", "type": "string"},
{"name": "age", "type": "int"},
{"name": "email", "type": ["null", "string"], "default": null}
]
}
"""
schem…How to mock an external service in Python with an anti-corruption facade
This code implements an anti-corruption facade that mocks an external API, allowing client code to interact with a simulated service while keeping the same interface.
class AntiCorruptionFacade:
"""Mocks a real API while keeping the same interface."""
def __init__(self, data_store):
self._data_store = data_store
self._calls = []
def get_user(self, user_id):
self._calls.append(f"get_user({user_id})")
return self._data_store.get(u…How to Stage ML Model Workflows with Python Classes
Defines a Stage class to model ML pipeline stages with variants and mocks, printing grammar for Model, Staging, and Production stages.
class Stage:
def __init__(self, name):
self.name = name
self.mocks = []
self.variants = []
def add_mock(self, mock_name):
self.mocks.append(mock_name)
def add_variant(self, variant_name, productions=()):
self.variants.append((variant_name, list(productions)))
…How to Do Random Assignment in Python for A/B Tests
Assign each item to a binary group (0 or 1) with uniform probability using a small reusable function, optionally weighted, for A/B testing mocks.
import random
def random_assignment_uniform_mock(items, weights=None):
"""Assign each item to a group (0 or 1) with uniform probability."""
if weights is None:
# Default: each item independently gets 0 or 1 with 50% probability
return [random.randint(0, 1) for _ in items]
# Optional weight…How to Replicate Data Across All Shards in Python
Mocks a global table that replicates a key-value pair to every shard, ensuring reads return the same value from any shard.
from dataclasses import dataclass
from typing import Dict, List
@dataclass
class Shard:
id: str
data: Dict[str, int]
class GlobalTable:
def __init__(self, shards: List[Shard]):
self._shards = {s.id: s for s in shards}
def set_value(self, key: str, value: int) -> None:
"""Replicate …How to Test X-Content-Type-Options nosniff in Python with Mocks
Mock httpx responses and verify that a server's X-Content-Type-Options header includes nosniff to prevent MIME sniffing.
import httpx
from unittest.mock import Mock, patch
def fetch_headers(url: str) -> dict:
response = httpx.get(url)
return dict(response.headers)
def mock_nosniff_check(response) -> bool:
content_type = response.headers.get("content-type", "")
x_content_type_options = response.headers.get("x-content-ty…How to implement OCSP stapling mock in Python
Simulate OCSP stapling with a caching mechanism that mocks certificate status lookups for TLS handshake validation.
import hashlib
import time
class OCSPStapler:
def __init__(self, cert_serial: str, issuer_hash: str):
self.cert_serial = cert_serial
self.issuer_hash = issuer_hash
self.cache = {}
def _mock_query_ocsp(self, serial: str) -> dict:
"""Simulate OCSP responder lookup."""
di…OAuth2 authorization code flow mock in Python
A minimal HTTP server that mocks the OAuth2 authorization code flow, issuing codes via /authorize and exchanging them for tokens at /token.
import json
from http.server import BaseHTTPRequestHandler, HTTPServer
from urllib.parse import urlparse, parse_qs
AUTH_CODE_STORE = {}
CLIENT_ID = "demo-client"
REDIRECT_URI = "http://localhost:8000/callback"
class OAuthHandler(BaseHTTPRequestHandler):
def do_GET(self):
parsed = urlparse(self.path)
…How to Mock time.sleep in a Python PreStop Hook
This code simulates a Kubernetes PreStop hook that delays shutdown, then mocks time.sleep to verify the hook logic without real delay.
import subprocess
import sys
import time
from unittest.mock import patch
def pre_stop_hook():
"""Simulate a Kubernetes PreStop hook that sleeps before shutdown."""
print("PreStop hook started: delaying shutdown")
time.sleep(3)
print("PreStop hook completed: ready to shutdown")
if __name__ == "__main_…Mock ConfigMap Mount Environment Variables in Python
Simulate reading environment variables from a Kubernetes ConfigMap-mounted directory and test it with mocks.
import os
import tempfile
from unittest.mock import patch
def load_config_from_mount(mount_path):
"""Simulate reading environment variables from a ConfigMap-mounted directory."""
config = {}
for filename in os.listdir(mount_path):
file_path = os.path.join(mount_path, filename)
if os.path.i…Browse by section
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