Allow Fixture customization (#10)

Source/SweetBuilders/BuilderBase.cs

@@ -19,28 +19,35 @@ public abstract class BuilderBase<TObject, TBuilder>
     /// <summary>
     /// Initializes a new instance of the <see cref="BuilderBase{TObject, TBuilder}"/> class.
     /// </summary>
-    protected BuilderBase() => this.Composer = this.Fixture.Build<TObject>()
-            .FromFactory(Factories.Default<TObject>);
+    protected BuilderBase()
+        : this(CreateComposer())
+    {
+    }
 
     /// <summary>
     /// Initializes a new instance of the <see cref="BuilderBase{TObject, TBuilder}"/> class.
     /// </summary>
-    /// <param name="factory">A factory of the <typeparamref name="TObject"/> class.</param>
+    /// <param name="factory">A factory of <typeparamref name="TObject"/>.</param>
     protected BuilderBase(Func<TObject> factory)
+        : this(CreateComposer().FromFactory(factory))
     {
-        if (factory == null)
-        {
-            throw new ArgumentNullException(nameof(factory));
-        }
-
-        var customizationComposer = this.Fixture.Build<TObject>();
-        this.Composer = customizationComposer.FromFactory(factory);
     }
 
-    private Fixture Fixture { get; } = new Fixture
+    /// <summary>
+    /// Initializes a new instance of the <see cref="BuilderBase{TObject, TBuilder}"/> class.
+    /// </summary>
+    /// <param name="fixture">The fixture that will be used to initialize the builder.</param>
+    protected BuilderBase(Fixture fixture)
+        : this(CreateComposer(fixture))
     {
-        OmitAutoProperties = true,
-    };
+    }
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="BuilderBase{TObject, TBuilder}"/> class.
+    /// </summary>
+    /// <param name="composer">The composer that will be used by the builder.</param>
+    protected BuilderBase(IPostprocessComposer<TObject>? composer = null)
+        => this.Composer = composer ?? CreateComposer();
 
     private IPostprocessComposer<TObject> Composer { get; set; }
 
@@ -285,4 +292,15 @@ public TBuilder Without<TProperty>(Expression<Func<TObject, TProperty>> property
     /// <param name="count">The number of objects to create.</param>
     /// <returns>A sequence of anonymous objects of type <typeparamref name="TObject"/>.</returns>
     public IEnumerable<TObject> CreateMany(int count) => this.Composer.CreateMany(count);
+
+    private static Fixture CreateFixture() => new()
+    {
+        OmitAutoProperties = true,
+    };
+
+    private static ICustomizationComposer<TObject> CreateComposer(Fixture? fixture = null)
+    {
+        fixture ??= CreateFixture();
+        return fixture.Build<TObject>();
+    }
 }

Tests/SweetBuilders.Test/BuilderBaseTests.cs

@@ -268,30 +268,33 @@ public void ShouldCreateNInstancies()
     }
 
     [Fact]
-    public void ShouldThrowIfFactoryIsNull()
+    public void ShouldThrowIfPropertyNameIsNull()
     {
-        var act = () => new FooBarInvalidBuilder();
+        var builder = Builder<Foo>.New;
+
+#pragma warning disable CS8625 // Cannot convert null literal to non-nullable reference type.
+        var act = () => builder.WithPrivate(null, string.Empty);
+#pragma warning restore CS8625 // Cannot convert null literal to non-nullable reference type.
 
         using (new AssertionScope())
         {
             act.Should().Throw<ArgumentNullException>()
-                .WithParameterName("factory");
+                .WithParameterName("propertyName");
         }
     }
 
     [Fact]
-    public void ShouldThrowIfPropertyNameIsNull()
+    public void ShouldRespectFixtureCustomizations()
     {
-        var builder = Builder<Foo>.New;
-
-#pragma warning disable CS8625 // Cannot convert null literal to non-nullable reference type.
-        var act = () => builder.WithPrivate(null, string.Empty);
-#pragma warning restore CS8625 // Cannot convert null literal to non-nullable reference type.
+        var foo = new FooBuilderCustomFixture()
+            .Create();
 
         using (new AssertionScope())
         {
-            act.Should().Throw<ArgumentNullException>()
-                .WithParameterName("propertyName");
+            foo.Bar.Should().NotBeNull("the builder should generate all public properties");
+            foo.Bar?.Name.Should().Be(
+                FooBuilderCustomFixture.NAME,
+                "the builder should respect any Fixture customizations");
         }
     }
 

Tests/SweetBuilders.Test/FooBar.cs

@@ -1,6 +1,7 @@
 namespace SweetBuilders.Test;
 
 using System;
+using AutoFixture;
 
 #pragma warning disable CS0169, IDE0051 // Remove unused private members
 #pragma warning disable SA1649 // File name should match first type name
@@ -53,14 +54,24 @@ internal class BarBuilder : BuilderBase<Bar, BarBuilder>
     public BarBuilder() => this.With(x => x.Name, NAME);
 }
 
-internal class FooBarInvalidBuilder : BuilderBase<Foo, FooBarInvalidBuilder>
+internal class FooBuilderCustomFixture : BuilderBase<Foo, FooBuilderCustomFixture>
 {
-#pragma warning disable CS8625 // Cannot convert null literal to non-nullable reference type.
-    public FooBarInvalidBuilder()
-        : base(null)
+    internal static readonly string NAME = Guid.NewGuid().ToString();
+
+    public FooBuilderCustomFixture()
+        : base(CreateFixture())
+    {
+    }
+
+    private static Fixture CreateFixture()
     {
+        var fixture = new Fixture
+        {
+            OmitAutoProperties = false,
+        };
+        fixture.Customize<Bar>(bar => bar.With(x => x.Name, NAME));
+        return fixture;
     }
-#pragma warning restore CS8625 // Cannot convert null literal to non-nullable reference type.
 }
 #pragma warning restore CS0169, IDE0051 // Remove unused private members
 #pragma warning restore SA1649 // File name should match first type name