pytest-unique

Pytest fixture to generate unique values.

Requirements

You will need the following prerequisites to use pytest-unique:

• Python 3.9, 3.10, 3.11, 3.12, 3.13

Installation

To install pytest-unique:

$ pip install pytest-unique

Usage

You can use the unique fixture by passing it as a test argument:

def test_integer(unique):
    assert unique("integer") > 0

Here are some of the plugins available by default:

• bytes with invalid UTF8 characters.
• digits with just numbers.
• email with a unique username.
• float with a whole part and a decimal part.
• integer with base and mod arguments.
• password with lowercase, uppercase, digits and punctuation arguments.
• text with prefix, suffix and separator arguments.

Extensions

The unique fixture can be extended with custom plugins:

from datetime import datetime, timezone

def unique_datetime(unique)
    """Return a datetime unique to this factory instance."""
    timestamp = unique("integer")
    return datetime.fromtimestamp(timestamp, timezone.utc)

Then, add it to the pyproject.toml file of your project:

[tool.poetry.plugins."pytest_unique"]
datetime = "your_project.unique:unique_datetime"

You can then use the plugin like all other plugins:

from datetime import datetime

def test_datetime(unique):
    assert isinstance(unique("datetime"), datetime)

Limitations

The unique fixture cannot be used as parameters in parameterized tests by virtue of being a fixture. The reason it is a fixture rather than a function is that unique values are generated from an instance of a counter that returns sequential values. This makes it possible to see the order in which values were generated which can be useful when troubleshooting.

Resources

• Documentation
• Release Notes
• Issue Tracker
• Source Code
• PyPi