Skip to content
Go to file


Build status


One of the more immediately applicable recommendations from Growing Object-Oriented Software, Guided by Tests (GOOS) is to make use of Test Data Builders, to allow you to construct test data with a fluent syntax, such as

			.WithFirstLine("123 Main Street")

This pattern is immensely powerful, but requires the writing of a lot of code for each type you wish to build. The aim of BobTheBuilder is to provide a generic implementation of the Test Data Builder pattern from GOOS, using C#'s support for dynamic dispatch to intelligently hydrate the destination object. For example, using the same hypothetical types as above:

Customer customer = A.BuilderFor<Customer>()
                                    .WithFirstLine("123 Main Street")

Note that a dynamic builder can be implicitly cast to the type it builds and the Build() method will be automatically invoked. This saves you a bit of typing if desired and reduces noise, but requires you to explicitly state your variable types; it comes into its own when nesting builders, though, as in the example above.

Task List

  • Add support for readonly properties via the constructor
  • Add support for objects with constructor dependencies
  • Add support for complex types (Complete)
  • Add support for named arguments syntax (.With(stringProperty: "new value")) (Complete)
  • Get a better name...

Please request features and report bugs, or better still fork me and send me a pull request.


The idea for this library was partially inspired by previous exposure to Simple.Data, and the number of Test Data Builders I have written in the last twelve months. Thanks Steve and Nat for such an elegantly simple, and yet extremely powerful, piece of advice.


Can we build it? Yes we can!




No releases published


No packages published


You can’t perform that action at this time.