我试图用Autofixture控制对象树的生成深度。在某些情况下，我只想生成根对象，在另一组情况下，我可能想要生成一个特定深度的树（2,3，比方说）。
class Foo {
public string Name {get;set;}
public Bar Bar {get;set;}
public AnotherType Xpto {get;set;}
public YetAnotherType Xpto {get;set;}
}
class Bar {
public string Name {get;set;}
public string Description {get;set;}
public AnotherType Xpto {get;set;}
public YetAnotherType Xpto {get;set;}
public Xpto Xpto {get;set;}
}
class Xpto {
public string Description {get;set;}
public AnotherType Xpto {get;set;}
public YetAnotherType Xpto {get;set;}
}
通过上面的例子，我希望（深度1）控制生成过程，以便只实例化Foo类，并且不填充该类的Bar属性或任何其他引用类型，或者（深度2）我想要Foo类实例化后，Bar属性使用新的Bar实例填充，但Xpto属性或该类上的任何其他引用类型未填充。
如果我没有在代码库中发现它，Autofixture是否有自定义或行为允许我们进行这种控制？
同样，我想要控制的不是递归，而是对象图的填充深度。
没有酒吧
一次性：
var f = fixture.Build<Foo>().Without(f => f.Bar).Create();
可重复使用：
fixture.Customize<Foo>(c => c.Without(f => f.Bar));
var f = fixture.Create<Foo>();
没有Xpto
一次性：
var f = fixture
.Build<Foo>()
.With(
f => f.Bar,
fixture.Build<Bar>().Without(b => b.Xpto).Create())
.Create();
可重复使用：
fixture.Customize<Bar>(c => c.Without(b => b.Xpto));
var f = fixture.Create<Foo>();
在这里你去GenerationDepthBehavior
fixture.Behaviors.Add（new GenerationDepthBehavior（2））;
public class GenerationDepthBehavior : ISpecimenBuilderTransformation
{
private const int DefaultGenerationDepth = 1;
private readonly int generationDepth;
public GenerationDepthBehavior() : this(DefaultGenerationDepth)
{
}
public GenerationDepthBehavior(int generationDepth)
{
if (generationDepth < 1)
throw new ArgumentOutOfRangeException(nameof(generationDepth), "Generation depth must be greater than 0.");
this.generationDepth = generationDepth;
}
public ISpecimenBuilderNode Transform(ISpecimenBuilder builder)
{
if (builder == null) throw new ArgumentNullException(nameof(builder));
return new GenerationDepthGuard(builder, new GenerationDepthHandler(), this.generationDepth);
}
}
public interface IGenerationDepthHandler
{
object HandleGenerationDepthLimitRequest(object request, IEnumerable<object> recordedRequests, int depth);
}
public class DepthSeededRequest : SeededRequest
{
public int Depth { get; }
public int MaxDepth { get; set; }
public bool ContinueSeed { get; }
public int GenerationLevel { get; private set; }
public DepthSeededRequest(object request, object seed, int depth) : base(request, seed)
{
Depth = depth;
Type innerRequest = request as Type;
if (innerRequest != null)
{
bool nullable = Nullable.GetUnderlyingType(innerRequest) != null;
ContinueSeed = nullable || innerRequest.IsGenericType;
if (ContinueSeed)
{
GenerationLevel = GetGenerationLevel(innerRequest);
}
}
}
private int GetGenerationLevel(Type innerRequest)
{
int level = 0;
if (Nullable.GetUnderlyingType(innerRequest) != null)
{
level = 1;
}
if (innerRequest.IsGenericType)
{
foreach (Type generic in innerRequest.GetGenericArguments())
{
level++;
level += GetGenerationLevel(generic);
}
}
return level;
}
}
public class GenerationDepthGuard : ISpecimenBuilderNode
{
private readonly ThreadLocal<Stack<DepthSeededRequest>> requestsByThread
= new ThreadLocal<Stack<DepthSeededRequest>>(() => new Stack<DepthSeededRequest>());
private Stack<DepthSeededRequest> GetMonitoredRequestsForCurrentThread() => this.requestsByThread.Value;
public GenerationDepthGuard(ISpecimenBuilder builder)
: this(builder, EqualityComparer<object>.Default)
{
}
public GenerationDepthGuard(
ISpecimenBuilder builder,
IGenerationDepthHandler depthHandler)
: this(
builder,
depthHandler,
EqualityComparer<object>.Default,
1)
{
}
public GenerationDepthGuard(
ISpecimenBuilder builder,
IGenerationDepthHandler depthHandler,
int generationDepth)
: this(
builder,
depthHandler,
EqualityComparer<object>.Default,
generationDepth)
{
}
public GenerationDepthGuard(ISpecimenBuilder builder, IEqualityComparer comparer)
{
this.Builder = builder ?? throw new ArgumentNullException(nameof(builder));
this.Comparer = comparer ?? throw new ArgumentNullException(nameof(comparer));
this.GenerationDepth = 1;
}
public GenerationDepthGuard(
ISpecimenBuilder builder,
IGenerationDepthHandler depthHandler,
IEqualityComparer comparer)
: this(
builder,
depthHandler,
comparer,
1)
{
}
public GenerationDepthGuard(
ISpecimenBuilder builder,
IGenerationDepthHandler depthHandler,
IEqualityComparer comparer,
int generationDepth)
{
if (builder == null) throw new ArgumentNullException(nameof(builder));
if (depthHandler == null) throw new ArgumentNullException(nameof(depthHandler));
if (comparer == null) throw new ArgumentNullException(nameof(comparer));
if (generationDepth < 1)
throw new ArgumentOutOfRangeException(nameof(generationDepth), "Generation depth must be greater than 0.");
this.Builder = builder;
this.GenerationDepthHandler = depthHandler;
this.Comparer = comparer;
this.GenerationDepth = generationDepth;
}
public ISpecimenBuilder Builder { get; }
public IGenerationDepthHandler GenerationDepthHandler { get; }
public int GenerationDepth { get; }
public int CurrentDepth { get; }
public IEqualityComparer Comparer { get; }
protected IEnumerable RecordedRequests => this.GetMonitoredRequestsForCurrentThread();
public virtual object HandleGenerationDepthLimitRequest(object request, int currentDepth)
{
return this.GenerationDepthHandler.HandleGenerationDepthLimitRequest(
request,
this.GetMonitoredRequestsForCurrentThread(), currentDepth);
}
public object Create(object request, ISpecimenContext context)
{
if (request is SeededRequest)
{
int currentDepth = 0;
var requestsForCurrentThread = GetMonitoredRequestsForCurrentThread();
if (requestsForCurrentThread.Count > 0)
{
currentDepth = requestsForCurrentThread.Max(x => x.Depth) + 1;
}
DepthSeededRequest depthRequest = new DepthSeededRequest(((SeededRequest)request).Request, ((SeededRequest)request).Seed, currentDepth);
if (depthRequest.Depth >= GenerationDepth)
{
var parentRequest = requestsForCurrentThread.Peek();
depthRequest.MaxDepth = parentRequest.Depth + parentRequest.GenerationLevel;
if (!(parentRequest.ContinueSeed && currentDepth < depthRequest.MaxDepth))
{
return HandleGenerationDepthLimitRequest(request, depthRequest.Depth);
}
}
requestsForCurrentThread.Push(depthRequest);
try
{
return Builder.Create(request, context);
}
finally
{
requestsForCurrentThread.Pop();
}
}
else
{
return Builder.Create(request, context);
}
}
public virtual ISpecimenBuilderNode Compose(
IEnumerable<ISpecimenBuilder> builders)
{
var composedBuilder = ComposeIfMultiple(
builders);
return new GenerationDepthGuard(
composedBuilder,
this.GenerationDepthHandler,
this.Comparer,
this.GenerationDepth);
}
internal static ISpecimenBuilder ComposeIfMultiple(IEnumerable<ISpecimenBuilder> builders)
{
ISpecimenBuilder singleItem = null;
List<ISpecimenBuilder> multipleItems = null;
bool hasItems = false;
using (var enumerator = builders.GetEnumerator())
{
if (enumerator.MoveNext())
{
singleItem = enumerator.Current;
hasItems = true;
while (enumerator.MoveNext())
{
if (multipleItems == null)
{
multipleItems = new List<ISpecimenBuilder> { singleItem };
}
multipleItems.Add(enumerator.Current);
}
}
}
if (!hasItems)
{
return new CompositeSpecimenBuilder();
}
if (multipleItems == null)
{
return singleItem;
}
return new CompositeSpecimenBuilder(multipleItems);
}
public virtual IEnumerator<ISpecimenBuilder> GetEnumerator()
{
yield return this.Builder;
}
IEnumerator IEnumerable.GetEnumerator()
{
return this.GetEnumerator();
}
}
public class GenerationDepthHandler : IGenerationDepthHandler
{
public object HandleGenerationDepthLimitRequest(
object request,
IEnumerable<object> recordedRequests, int depth)
{
return new OmitSpecimen();
}
}
github问题中请求了此功能。它最终被拒绝了。然而，它被拒绝了，因为在问题中发布了一个很好的，简单的解决方案。
public class GenerationDepthBehavior: ISpecimenBuilderTransformation
{
public int Depth { get; }
public GenerationDepthBehavior(int depth)
{
Depth = depth;
}
public ISpecimenBuilderNode Transform(ISpecimenBuilder builder)
{
return new RecursionGuard(builder, new OmitOnRecursionHandler(), new IsSeededRequestComparer(), Depth);
}
private class IsSeededRequestComparer : IEqualityComparer
{
bool IEqualityComparer.Equals(object x, object y)
{
return x is SeededRequest && y is SeededRequest;
}
int IEqualityComparer.GetHashCode(object obj)
{
return obj is SeededRequest ? 0 : EqualityComparer<object>.Default.GetHashCode(obj);
}
}
}
https://github.com/AutoFixture/AutoFixture/issues/1032#issuecomment-385928866