Test Data Generator

Generate realistic, structured test data for testing.

Quick Generation with Python Faker

Reference: https://faker.readthedocs.io/en/master/

Install

pip install faker

Chinese Locale Data

from faker import Faker

fake = Faker('zh_CN')

# Basic personal info
print(fake.name())           # 张三
print(fake.phone_number())   # 13800138000
print(fake.address())        # 北京市朝阳区...
print(fake.company())        # XX科技有限公司
print(fake.email())          # zhangsan@example.com
print(fake.ssn())            # 身份证号 (18位)
print(fake.credit_card_number())  # 银行卡号

# Date/time
print(fake.date_of_birth(minimum_age=18, maximum_age=65))
print(fake.date_between(start_date='-1y', end_date='today'))

Batch Generation Script

Use scripts/gen_data.py for batch data generation:

# Generate 100 users as JSON
python3 scripts/gen_data.py --type users --count 100 --format json --output users.json

# Generate 500 orders as CSV
python3 scripts/gen_data.py --type orders --count 500 --format csv --output orders.csv

# Generate SQL INSERT statements
python3 scripts/gen_data.py --type users --count 50 --format sql --table users --output seed.sql

Data Generation Patterns

User Data

from faker import Faker
import json, random

fake = Faker('zh_CN')

def gen_user(uid):
    return {
        "id": uid,
        "name": fake.name(),
        "email": fake.ascii_free_email(),
        "phone": fake.phone_number(),
        "id_card": fake.ssn(),
        "gender": random.choice(["male", "female"]),
        "birth_date": str(fake.date_of_birth(minimum_age=18, maximum_age=60)),
        "address": fake.address(),
        "created_at": str(fake.date_time_between(start_date='-2y')),
        "status": random.choices(["active", "inactive", "banned"],
                                weights=[85, 10, 5])[0],
    }

users = [gen_user(i) for i in range(1, 101)]
print(json.dumps(users, ensure_ascii=False, indent=2))

Order Data (with foreign keys)

def gen_order(oid, user_ids, product_ids):
    qty = random.randint(1, 10)
    price = round(random.uniform(9.9, 999.9), 2)
    return {
        "id": oid,
        "user_id": random.choice(user_ids),
        "product_id": random.choice(product_ids),
        "quantity": qty,
        "unit_price": price,
        "total": round(qty * price, 2),
        "status": random.choices(
            ["pending", "paid", "shipped", "delivered", "cancelled"],
            weights=[10, 20, 25, 40, 5])[0],
        "created_at": str(fake.date_time_between(start_date='-6m')),
        "address": fake.address(),
    }

Boundary & Edge Case Data

Always include these special values in test datasets:

EDGE_CASES = {
    "string": [
        "",                          # empty
        " ",                         # whitespace only
        "a" * 256,                   # max length
        "a" * 257,                   # over max length
        "<script>alert(1)</script>", # XSS
        "' OR 1=1 --",              # SQLi
        "张三\x00李四",              # null byte
        "🔍 emoji test 🎉",         # emoji
        "Ñoño café résumé",         # unicode accents
    ],
    "number": [0, -1, 1, 2147483647, -2147483648, 0.001, 99999999.99],
    "date": ["1970-01-01", "2099-12-31", "2000-02-29", "2001-02-29"],  # leap year
    "phone": ["13800138000", "19900001111", "12345678901", "1380013800"],  # boundary
}

Output Formats

SQL INSERT

def to_sql(users, table="users"):
    cols = users[0].keys()
    lines = [f"INSERT INTO {table} ({','.join(cols)}) VALUES"]
    for i, u in enumerate(users):
        vals = []
        for v in u.values():
            if v is None:
                vals.append("NULL")
            elif isinstance(v, (int, float)):
                vals.append(str(v))
            else:
                vals.append(f"'{str(v).replace(chr(39), chr(39)*2)}'")
        sep = "," if i < len(users) - 1 else ";"
        lines.append(f"  ({','.join(vals)}){sep}")
    return "\n".join(lines)

CSV

import csv

def to_csv(data, filepath):
    with open(filepath, 'w', newline='', encoding='utf-8-sig') as f:
        writer = csv.DictWriter(f, fieldnames=data[0].keys())
        writer.writeheader()
        writer.writerows(data)

JSON Fixture

def to_json(data, filepath):
    with open(filepath, 'w', encoding='utf-8') as f:
        json.dump(data, f, ensure_ascii=False, indent=2, default=str)

Chinese ID Card Validation

Reference: GB 11643-1999 (公民身份号码标准)

def validate_id_card(id_number: str) -> bool:
    """Validate Chinese 18-digit ID card number per GB 11643-1999."""
    if len(id_number) != 18:
        return False
    weights = [7, 9, 10, 5, 8, 4, 2, 1, 6, 3, 7, 9, 10, 5, 8, 4, 2]
    check_codes = '10X98765432'
    try:
        total = sum(int(id_number[i]) * weights[i] for i in range(17))
        return check_codes[total % 11] == id_number[17].upper()
    except (ValueError, IndexError):
        return False

def gen_valid_id_card():
    """Generate a valid Chinese ID card number with correct checksum."""
    import random
    # Area codes (sample: Beijing, Shanghai, Guangdong)
    areas = ['110101', '310101', '440106', '330102', '510104']
    area = random.choice(areas)
    birth = fake.date_of_birth(minimum_age=18, maximum_age=60).strftime('%Y%m%d')
    seq = f"{random.randint(0, 999):03d}"
    base = area + birth + seq
    weights = [7, 9, 10, 5, 8, 4, 2, 1, 6, 3, 7, 9, 10, 5, 8, 4, 2]
    check_codes = '10X98765432'
    total = sum(int(base[i]) * weights[i] for i in range(17))
    return base + check_codes[total % 11]

Data Masking / Desensitization

For copying production data to test environments:

def mask_phone(phone: str) -> str:
    """138****8000"""
    if len(phone) >= 11:
        return phone[:3] + "****" + phone[7:]
    return "***"

def mask_id_card(id_card: str) -> str:
    """110101****0001"""
    if len(id_card) >= 18:
        return id_card[:6] + "********" + id_card[14:]
    return "***"

def mask_name(name: str) -> str:
    """张*"""
    if len(name) >= 2:
        return name[0] + "*" * (len(name) - 1)
    return "*"

def mask_email(email: str) -> str:
    """z***@example.com"""
    local, domain = email.split("@")
    return local[0] + "***@" + domain

def mask_bank_card(card: str) -> str:
    """6222 **** **** 1234"""
    if len(card) >= 16:
        return card[:4] + " **** **** " + card[-4:]
    return "****"

Tips

• Always use ensure_ascii=False for Chinese JSON output
• Use utf-8-sig encoding for CSV files opened in Excel
• Set Faker.seed(42) for reproducible test data
• Mix normal data (90%) with edge cases (10%) for realistic coverage
• Include data relationships (FK references) when generating related tables
• For large datasets (>10k rows), use batch inserts and transactions