philiprehberger-data-factory 0.4.0

Lightweight test data generation with realistic fake values.

philiprehberger-data-factory

Lightweight test data generation with realistic fake values.

Installation

pip install philiprehberger-data-factory

Usage

Generate fake values

from philiprehberger_data_factory import fake

fake.name()      # "Alice Johnson"
fake.email()     # "[e-mail]"
fake.integer()   # 472
fake.boolean()   # True
fake.text()      # "alpha bravo charlie delta echo"
fake.date()      # "2023-07-14"
fake.uuid()      # "a3b2c1d4-..."
fake.phone()     # "[phone]"
fake.address()   # "742 Oak Street, Springfield"

Factory

Define a schema and generate records in bulk:

from philiprehberger_data_factory import Factory

user_factory = Factory({
    "name": "name",
    "email": "email",
    "age": "integer",
    "bio": "text",
    "joined": "date",
    "id": "uuid",
    "phone": "phone",
    "address": "address",
})

user = user_factory.build()
# {'name': 'Grace Wilson', 'email': '[e-mail]', ...}

users = user_factory.build_batch(100)
# [{'name': ..., 'email': ..., ...}, ...]

Bulk generation with overrides

Use batch() to generate multiple records with optional per-item or shared overrides:

from philiprehberger_data_factory import Factory

factory = Factory({"name": "name", "role": "text"})

# Shared overrides applied to every record
admins = factory.batch(5, overrides={"role": "admin"})

# Per-item overrides
records = factory.batch(3, overrides=[
    {"role": "admin"},
    {"role": "editor"},
    {"role": "viewer"},
])

Relationship / foreign-key support

Link factories so generated objects have consistent foreign-key references:

from philiprehberger_data_factory import Factory

user_factory = Factory({"id": "uuid", "name": "name"})
user = user_factory.build()

post_factory = Factory({"title": "text", "body": "text"})
post_factory.related(user_factory, field="user_id", source_field="id")

post = post_factory.build()
# post["user_id"] matches user["id"]

Statistical distribution profiles

Generate numeric fields following statistical distributions:

from philiprehberger_data_factory import Factory

factory = Factory({"name": "name"})
factory.field("age", distribution="normal", mean=30, std=10)
factory.field("score", distribution="uniform", min=0, max=100)
factory.field("wait_time", distribution="exponential", scale=5.0)

record = factory.build()
# {'name': 'Alice Johnson', 'age': 28.4, 'score': 73.2, 'wait_time': 3.1}

Weighted choices

from philiprehberger_data_factory import fake

tier = fake.weighted_choice({"gold": 0.1, "silver": 0.3, "bronze": 0.6})

Custom providers

Pass a callable instead of a provider string:

from philiprehberger_data_factory import fake, Factory

factory = Factory({
    "name": "name",
    "role": lambda: fake.choice(["admin", "editor", "viewer"]),
})

Reproducible output

from philiprehberger_data_factory import fake

fake.seed(42)
fake.name()  # always the same name for seed 42

Auto-incrementing IDs with sequence_field

from philiprehberger_data_factory import Factory

users = Factory({"name": "name", "email": "email"}).sequence_field("id")
users.build_batch(3)
# [{"id": 1, "name": ..., ...}, {"id": 2, ...}, {"id": 3, ...}]

# Custom start / step
orders = Factory({}).sequence_field("order_no", start=1000, step=5)

Each factory owns its own counter, so two factories that share the same schema produce independent sequences without colliding.

API

Function / Class	Description
fake.name()	Random full name
fake.email()	Random email address
fake.integer(min, max)	Random integer (default 0-1000)
fake.decimal(min, max, precision)	Random float (default 0-1000, 2 decimals)
fake.boolean()	Random True or False
fake.choice(items)	Random element from a list
fake.text(words)	Random words (default 5)
fake.date(start, end)	Random ISO date string
fake.uuid()	Random UUID4 string
fake.phone()	Random phone number in +1-XXX-XXX-XXXX format
fake.address()	Random street address with city
fake.weighted_choice(options)	Weighted random selection from a dict of options to weights
fake.normal(mean, std)	Random float from a normal distribution
fake.exponential(scale)	Random float from an exponential distribution
fake.seed(n)	Set random seed for reproducibility
Factory(schema)	Create a factory from a schema dict
factory.build(**overrides)	Generate one record with optional field overrides
factory.build_batch(n)	Generate n records
factory.batch(n, overrides)	Generate n records with shared or per-item overrides
factory.field(name, distribution, **params)	Add a field with a statistical distribution (normal, uniform, exponential)
factory.related(other, field, source_field)	Link to another factory for foreign-key consistency
factory.sequence_field(name, start=1, step=1)	Register a monotonically increasing integer field (per-factory counter)

Development

pip install -e .
python -m pytest tests/ -v

Support

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License

MIT