LochNessBuilder 2.1.0

LochNessBuilder

A C# Builder library to automate creation of objects for tests

Migration Guide

Do not use v2.0.0

This version was released inadvertantly and has been deprecated and de-listed from nuget.org

Versions 2.1 and 3.0-alpha are available

• If you wanted "v1.x but on .NET Standard", then use v2.1.
• If you really wanted "the version that was released as v2.0.0" then use v3.0-alpha, though this is not release-ready and should only be used if you've already integrated against the inadvertant v2.0.0 release.

Migration from v1.0 to v2.1

No API changes. No Migration required. MIT License was added.

Use in a .Net Framework project

As of version 2.0, this library has been migrated to .Net standard, to enable use in .Net core projects.

To continue consuming this library from a .Net Framework project, the following reference will need to be added to the .csproj file:

<Reference Include="netstandard" />

Examples

The builder for a number of Monsters:

using System.Linq;
using LochNessBuilder;

[Builder]
public static class MonsterBuilder
{
    public static Builder<Monster> New
    {
        get
        {
            return Builder<Monster>.New
                .With(t => t.Id, Enumerable.Range(1, int.MaxValue))
                .With(t => t.Name, Enumerable.Range(1, int.MaxValue).Select(i => $"Name {i}"));
        }
    }
}
  
public class Monster
{
  public int Id { get; set; }
  public string Name { get; set; }
}

How you would then build a number of Monsters for use in tests (using types in place of var for clarity):

// To build a single Monster
Monster testMonster = MonsterBuilder.New.Build();
// testMonster has Id = 1, Name = "Name 1"

// To build an enumerable of Monsters
IEnumerable<Monster> testMonsters = MonsterBuilder.New.Build(5);
// testMonsters has 5 Monsters, with Ids of respectively 1, 2, 3, 4, 5 and matching Names

// To build an enumerable of Monsters, each with a fixed Name
IEnumerable<Monster> nameMonsters = MonsterBuilder.New.WithPostBuildSetup(t => t.Name, "Constant").Build(4);
// nameMonsters have Ids 1-4 but all have name "Constant"

// To build an enumerable of Monsters, each with a name matching the previous monster's Id
string prevName = "0";
IEnumerable<Monster> seqMonsters = MonsterBuilder.New
    .WithSetup(t => t.Name = prevName)
    .WithPostBuildSetup(t => prevName = t.Id.ToString()
    .Build(3);
// seqMonsters have Ids 1, 2, 3 and Names "0", "1", "2"

Sometimes you may need a stateful Builder - for example, if there are constraints on uniqueness of certain properties.

// In the enclosing class
private Builder<Monster> monsterBuilder = MonsterBuilder.New;
// Then use this form in methods instead
Monster testMonster = monsterBuilder.Build();

Variations on the Builder

The builder can also be customised to build things differently. You can use factories (withFactory), setup (withSetup), post-build setup (withPostBuildSetup), collections (withCollection)

TODOs

• Update with more detailed documentation for Builder
• Better examples