29 Minimal Python Code Snippets for API Automation Testing

The article provides a collection of 29 minimal Python snippets useful for API automation testing, each with a brief explanation and sample output.

Example 1: JSON string to dict

import json
data = json.loads('{"key":"value"}')
print(data)

Example 2: Dict to JSON string

import json
json_str = json.dumps({"key": "value"}, ensure_ascii=False)
print(json_str)

Example 3: Read JSON file

import json
with open('file.json', 'w') as f:
    json.dump({"name": "test"}, f)
with open('file.json', 'r') as f:
    data = json.load(f)
print(data)

Example 4: Write dict to JSON file

import json
with open('file.json', 'w') as f:
    json.dump({"key": "value"}, f, ensure_ascii=False)

Example 5: Extract nested field

data = {"user": {"name": "张三"}}
name = data.get("user", {}).get("name")
print(name)

Example 6: Add new field

data = {"username": "admin"}
data["newKey"] = "newValue"
print(data)

Example 7: Delete field

data = {"key1": "val1", "key2": "val2"}
del data["key1"]
print(data)

Example 8: Check key existence

data = {"name": "Alice"}
print("name" in data)

Example 9: Iterate dictionary items

data = {"a": 1, "b": 2}
for key, value in data.items():
    print(key, value)

Example 10: Merge two dictionaries

dict1 = {"a": 1}
dict2 = {"b": 2}
merged = {**dict1, **dict2}
print(merged)

Example 11: Get default value

data = {"age": 25}
print(data.get("missing_key", "default_value"))

Example 12: Filter list

data = [{"name": "Tom", "age": 20}, {"name": "Jerry", "age": 15}]
filtered = [item for item in data if item['age'] > 18]
print(filtered)

Example 13: Compare two JSON objects (ignore order)

import json
d1 = {"a": 1, "b": 2}
d2 = {"b": 2, "a": 1}
print(json.dumps(d1, sort_keys=True) == json.dumps(d2, sort_keys=True))

Example 14: Output JSON sorted by keys

import json
data = {"b": 2, "a": 1, "c": 3}
sorted_json = json.dumps(data, sort_keys=True)
print(sorted_json)

Example 15: Validate status code

response_data = {"code": 200, "msg": "ok"}
if response_data.get("code") == 200:
    print("请求成功")

Example 16: Use token in request headers

import requests
token = "abc123"
headers = {"Authorization": f"Bearer {token}"}
print("请求头:", headers)

Example 17: jsonpath extraction

from jsonpath import jsonpath
data = {"store": {"book": [{"title": "Java 编程"}, {"title": "Python 自动化"}]}}
titles = jsonpath(data, "$.store.book[*].title")
print(titles)

Example 18: Convert Java‑style keys to Python‑style

def rename_keys(d):
    return {k.lower(): v for k, v in d.items()}
data = {"UserName": "Tom", "Age": "20"}
renamed = rename_keys(data)
print(renamed)

Example 19: Print JSON as table

from tabulate import tabulate
data = [{"name": "Alice", "age": 25}, {"name": "Bob", "age": 17}]
print(tabulate(data, headers="keys", tablefmt="grid"))

Example 20: Mock API response

import json
def mock_response():
    return json.dumps({"success": True})
print(mock_response())

Example 21: Response assertion

res = {"success": True}
assert res["success"] is True
print("断言通过")

Example 22: Simple SHA256 hashing

import hashlib
hash_obj = hashlib.sha256(b'Hello World')
print(hash_obj.hexdigest())

Example 23: URL encoding

from urllib.parse import quote
encoded = quote('http://example.com?param=你好')
print(encoded)

Example 24: URL decoding

from urllib.parse import unquote
decoded = unquote('http%3A//example.com%3Fparam%3D%E4%BD%A0%E5%A5%BD')
print(decoded)

Example 25: Time formatting

from datetime import datetime
formatted = datetime.now().strftime("%Y-%m-%d %H:%M:%S")
print(formatted)

Example 26: Exception handling

try:
    result = 1 / 0
except Exception as e:
    print(f"出现错误：{e}")

Example 27: Regex matching

import re
matches = re.findall(r'\d+', '订单ID是123456，电话是13800138000')
print(matches)

Example 28: String concatenation

parts = ["接口", "自动化", "测试"]
result = "-".join(parts)
print(result)

Example 29: List deduplication

items = [1, 2, 2, 3, 4, 4, 5]
unique = list(set(items))
print(unique)

The collection demonstrates essential Python techniques for handling JSON, performing HTTP requests, processing data, encrypting information, and managing errors, making it a handy reference for developers writing automated API tests.