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The .NET Autogenerator

Soenneker.Utils.AutoBogus

The .NET Autogenerator

This project is an automatic creator and populator for the fake data generator Bogus. It's a replacement for the abandoned AutoBogus library.

The goals:

  • Be fast
  • Support the latest types in .NET

It uses the fastest .NET Reflection cache: soenneker.reflection.cache. Bogus updates are automatically integrated.

.NET 6+ is supported.

Installation

dotnet add package Soenneker.Utils.AutoBogus

Usage

  • Create an AutoFaker instance:
var optionalConfig = new AutoFakerConfig();
var autoFaker = new AutoFaker(optionalConfig);
  • Call Generate<>() on any type you want:
var randomWord = autoFaker.Generate<string>();
var dictionary = autoFaker.Generate<Dictionary<int, string>>();
var order = autoFaker.Generate<Order>();
  • It's also possible to generate types via an argument:
var randomWord = autoFaker.Generate(typeof(string));
  • Set a faker, configuration, rules, etc:
autoFaker.Config.Faker = new Faker("de");
autoFaker.Config.RepeatCount = 3;
...

AutoFakerOverride

This is the recommended way for controlling type customization:

public class OrderOverride : AutoFakerOverride<Order>
{
    public override void Generate(AutoFakerOverrideContext context)
    {
        var target = (context.Instance as Order)!;
        target.Id = 123;
        
        // Faker is available
        target.Name = context.Faker.Random.Word();

        // AutoFaker is also available
        target.Customer = context.AutoFaker.Generate<Customer>();
     }
}

Then just add AutoFakerOverride to the AutoFaker.Config instance:

autoFaker.Config.Overrides = new List<AutoFakerGeneratorOverride>();
autoFaker.Config.Overrides.Add(new OrderOverride());

AutoFaker<T>

This inherits from Bogus.Faker, and can be used to designate rules specific to the AutoFaker instance.

var autoFaker = new AutoFaker<Order>());
autoFaker.RuleFor(x => x.Id, f => f.Random.Number());
var order = autoFaker.Generate();

Tips

  • ⚠️ Instantiating an AutoFaker takes a non-trivial amount of time because of Bogus Faker initialization (almost 1ms). It's recommended that a single instance be used if possible.
  • AutoFaker.GenerateStatic<T>() is also available, but should be avoided (as it creates a new AutoFaker/Faker on each call).

Notes

  • Some patterns that existed in AutoBogus have been removed due to the complexity and performance impact.
  • This is a work in progress. Contribution is welcomed.

Benchmarks

Soenneker.Utils.AutoBogus - AutoFaker

Method Mean Error StdDev
Generate_int 79.40 ns 0.635 ns 0.563 ns
Generate_string 241.35 ns 3.553 ns 3.324 ns
Generate_complex 6,782.34 ns 43.811 ns 38.837 ns

Soenneker.Utils.AutoBogus - AutoFaker<T>

Method Mean Error StdDev
Generate_string 283.6 ns 3.28 ns 3.07 ns
Generate_complex 8,504.0 ns 76.58 ns 67.89 ns

AutoBogus

Method Mean Error StdDev
Generate_int 1.17 ms 0.033 ms 0.026 ms
Generate_complex 10.91 ms 0.181 ms 0.236 ms

Bogus

Method Mean Error StdDev
Bogus_int 19.70 ns 0.176 ns 0.165 ns
Bogus_string 171.75 ns 2.763 ns 2.585 ns
Bogus_ctor 730,669.06 ns 8,246.622 ns 7,310.416 ns