add unit tests

src/Lamar.Testing/Bugs/Bug_398_service_registry_hash_collisions.cs

@@ -0,0 +1,142 @@
+using Lamar.IoC;
+using Shouldly;
+using System;
+using Xunit;
+
+namespace Lamar.Testing.Bugs;
+
+public class Bug_398_service_registry_hash_collisions
+{
+    [Fact]
+    public void GetHashCollisions_RegistryWithCollisions()
+    {
+        var registry = GetRegistryWithCollisions();
+
+        var collisions = registry.GetInstanceHashCollisions();
+
+        collisions.ShouldNotBeEmpty();
+    }
+
+    [Fact]
+    public void GetHashCollisions_RegistryWithoutCollisions()
+    {
+        var registry = GetRegistryWithoutCollisions();
+
+        var collisions = registry.GetInstanceHashCollisions();
+
+        collisions.ShouldBeEmpty();
+    }
+
+    [Fact]
+    public void TryRemoveHashCollisions_RegistryWithCollisions()
+    {
+        var registry = GetRegistryWithCollisions();
+
+        var removed = registry.TryRemoveInstanceHashCollisions();
+
+        removed.ShouldBeTrue();
+    }
+
+    [Fact]
+    public void TryRemoveHashCollisions_RegistryWithoutCollisions()
+    {
+        var registry = GetRegistryWithoutCollisions();
+
+        var removed = registry.TryRemoveInstanceHashCollisions();
+
+        removed.ShouldBeFalse();
+    }
+
+    [Fact]
+    public void HandleInstanceHashCollisions()
+    {
+        var registry = GetRegistryWithCollisions();
+
+        registry.TryRemoveInstanceHashCollisions();
+
+        registry.GetInstanceHashCollisions().ShouldBeEmpty();
+
+        var container = new Container(registry);
+        container.GetInstance<IFoo>().ShouldBeOfType<Foo>();
+        container.GetInstance<IBar>().ShouldBeOfType<Bar>();
+    }
+
+    [Fact]
+    public void MitigateInstanceHashCollisions()
+    {
+        var registry = GetRegistryWithCollisions();
+
+        registry.MitigateInstanceHashCollisions();
+
+        registry.GetInstanceHashCollisions().ShouldBeEmpty();
+
+        var container = new Container(registry);
+        container.GetInstance<IFoo>().ShouldBeOfType<Foo>();
+        container.GetInstance<IBar>().ShouldBeOfType<Bar>();
+    }
+
+    [Fact]
+    public void MitigateInstanceHashCollisionsThrowsAfterLimitReached()
+    {
+        var registry = GetRegistryWithCollisions();
+
+        var mitigateCollisions = () => registry.MitigateInstanceHashCollisions(0);
+
+        mitigateCollisions.ShouldThrow<LamarInstanceHashCollisionException>();
+    }
+
+    [Fact]
+    public void MitigateInstanceHashCollisionsUsesCustomRenamePolicy()
+    {
+        var registry = GetRegistryWithCollisions();
+
+        var instanceFoo = registry.For<IFoo>().Use<Foo>();
+        var instanceBar = registry.For<IBar>().Use<Bar>();
+
+        instanceFoo.Hash = instanceBar.Hash = 1;
+
+        registry.MitigateInstanceHashCollisions(instanceRenamePolicy: x => $"{x}.updated");
+
+        instanceFoo.Name.ShouldEndWith(".updated");
+        instanceBar.Name.ShouldEndWith(".updated");
+    }
+
+    [Fact]
+    public void NamedCollisionThrows()
+    {
+        var registry = new ServiceRegistry();
+
+        registry.For<IFoo>().Use<Foo>().Named("foo").Hash = 1;
+        registry.For<IBar>().Use<Bar>().Named("bar").Hash = 1;
+
+        Action handleCollisions = () => registry.TryRemoveInstanceHashCollisions();
+
+        handleCollisions.ShouldThrow<LamarInstanceHashCollisionException>();
+    }
+
+
+    private ServiceRegistry GetRegistryWithCollisions()
+    {
+        var registry = new ServiceRegistry();
+
+        registry.For<IFoo>().Use<Foo>().Hash = 1;
+        registry.For<IBar>().Use<Bar>().Hash = 1;
+
+        return registry;
+    }
+
+    private ServiceRegistry GetRegistryWithoutCollisions()
+    {
+        var registry = new ServiceRegistry();
+
+        registry.For<IFoo>().Use<Foo>().Hash = 1;
+        registry.For<IBar>().Use<Bar>().Hash = 2;
+
+        return registry;
+    }
+
+    public interface IFoo { }
+    public interface IBar { }
+    public class Foo : IFoo { }
+    public class Bar : IBar { }
+}

src/Lamar/IoC/LamarInstanceHashCollisionException.cs

@@ -7,8 +7,13 @@ namespace Lamar.IoC;
 
 public class LamarInstanceHashCollisionException : LamarException
 {
+    public int InstanceHash { get; }
+    public IEnumerable<Type> ServiceTypes { get; }
+
     public LamarInstanceHashCollisionException(int instanceHash, IEnumerable<Type> serviceTypes) : base(
         $"Duplicate hash '{instanceHash}' generated for services: {string.Join(", ", serviceTypes.Select(x => x.FullNameInCode()))}")
     {
+        InstanceHash = instanceHash;
+        ServiceTypes = serviceTypes;
     }
 }

src/Lamar/ServiceRegistry.HashCollisionMitigation.cs

@@ -8,10 +8,13 @@ namespace Lamar;
 
 public partial class ServiceRegistry
 {
+    internal static readonly Func<string, string> DefaultInstanceRenamePolicy = name => $"{name}_x";
+
     /// <summary>
     /// Finds and mitigates <see cref="Instance"/> hash code collisions in the current <see cref="ServiceRegistry"/> instance.<br/>
 	/// Hash codes are regenerated by renaming the instances where collisions exist with the provided <paramref name="instanceRenamePolicy"/>.<br/>
-	/// When the <paramref name="retryLimit"/> is met, and a hash collision is detected, a <see cref="LamarInstanceHashCollisionException" /> is thrown.
+	/// When the <paramref name="retryLimit"/> is met, and a hash collision is detected, a <see cref="LamarInstanceHashCollisionException" /> is thrown.<br/>
+    /// If no <paramref name="instanceRenamePolicy"/> is specified, the <see cref="DefaultInstanceRenamePolicy"/> will be used.
     /// </summary>
     /// <param name="retryLimit"></param>
     /// <param name="instanceRenamePolicy"></param>
@@ -21,7 +24,7 @@ public void MitigateInstanceHashCollisions(int retryLimit = 3, Func<string, stri
         bool shouldMitigateCollisions = true;
         int remaininingRetries = retryLimit;
 
-        Func<string, string> renameInstance = instanceRenamePolicy ?? (name => $"{name}_x");
+        Func<string, string> renameInstance = instanceRenamePolicy ?? DefaultInstanceRenamePolicy;
 
         while (shouldMitigateCollisions && remaininingRetries > 0)
         {
@@ -37,6 +40,8 @@ public void MitigateInstanceHashCollisions(int retryLimit = 3, Func<string, stri
         }
     }
 
+    internal bool TryRemoveInstanceHashCollisions() => TryRemoveInstanceHashCollisions(DefaultInstanceRenamePolicy);
+
     internal bool TryRemoveInstanceHashCollisions(Func<string, string> instanceRenamePolicy)
     {
         var hasCollision = false;
@@ -50,6 +55,8 @@ internal bool TryRemoveInstanceHashCollisions(Func<string, string> instanceRenam
         return hasCollision;
     }
 
+    internal void HandleInstanceHashCollisions(IGrouping<int, Instance> collision) => HandleInstanceHashCollisions(collision, DefaultInstanceRenamePolicy);
+
     internal void HandleInstanceHashCollisions(IGrouping<int, Instance> collision, Func<string, string> instanceRenamePolicy)
     {
         var namedInstances = collision.Where(x => x.IsExplicitlyNamed).ToList();