LambdaProvider -> serializable MemberMethodProvider

tests/ImageSharp.Tests/TestUtilities/Attributes/WithMemberFactoryAttribute.cs

@@ -31,21 +31,9 @@ namespace SixLabors.ImageSharp.Tests
 
         protected override object[] GetFactoryMethodArgs(MethodInfo testMethod, Type factoryType)
         {
-            MethodInfo m = testMethod.DeclaringType.GetMethod(this.memberMethodName);
-
-            Type[] args = factoryType.GetGenericArguments();
-            Type colorType = args.Single();
-
-            Type imgType = typeof(Image<>).MakeGenericType(colorType);
-
-            Type funcType = typeof(Func<>).MakeGenericType(imgType);
-
-            MethodInfo genericMethod = m.MakeGenericMethod(args);
-
-            Delegate d = genericMethod.CreateDelegate(funcType);
-            return new object[] { d };
+            return new object[] { testMethod.DeclaringType.FullName, this.memberMethodName};
         }
 
         protected override string GetFactoryMethodName(MethodInfo testMethod) => "Lambda";
     }
-}
+}

tests/ImageSharp.Tests/TestUtilities/ImageProviders/LambdaProvider.cs

@@ -1,34 +0,0 @@
-// Copyright (c) Six Labors and contributors.
-// Licensed under the Apache License, Version 2.0.
-
-using System;
-
-using SixLabors.ImageSharp.PixelFormats;
-
-namespace SixLabors.ImageSharp.Tests
-{
-    /// <summary>
-    /// Provides <see cref="Image{TPixel}" /> instances for parametric unit tests.
-    /// </summary>
-    /// <typeparam name="TPixel">The pixel format of the image</typeparam>
-    public abstract partial class TestImageProvider<TPixel>
-        where TPixel : struct, IPixel<TPixel>
-    {
-        private class LambdaProvider : TestImageProvider<TPixel>
-        {
-            private readonly Func<Image<TPixel>> factoryFunc;
-
-            public LambdaProvider()
-            {
-                throw new NotSupportedException();
-            }
-
-            public LambdaProvider(Func<Image<TPixel>> factoryFunc)
-            {
-                this.factoryFunc = factoryFunc;
-            }
-
-            public override Image<TPixel> GetImage() => this.factoryFunc();
-        }
-    }
-}

tests/ImageSharp.Tests/TestUtilities/ImageProviders/MemberMethodProvider.cs

@@ -0,0 +1,69 @@
+// Copyright (c) Six Labors and contributors.
+// Licensed under the Apache License, Version 2.0.
+
+using System;
+using System.Linq;
+using System.Reflection;
+using SixLabors.ImageSharp.PixelFormats;
+using Xunit.Abstractions;
+
+namespace SixLabors.ImageSharp.Tests
+{
+    /// <summary>
+    /// Provides <see cref="Image{TPixel}" /> instances for parametric unit tests.
+    /// </summary>
+    /// <typeparam name="TPixel">The pixel format of the image</typeparam>
+    public abstract partial class TestImageProvider<TPixel>
+        where TPixel : struct, IPixel<TPixel>
+    {
+        private class MemberMethodProvider : TestImageProvider<TPixel>
+        {
+            private string declaringTypeName;
+            private string methodName;
+            private Func<Image<TPixel>> factoryFunc;
+
+            public MemberMethodProvider()
+            {
+            }
+
+            public MemberMethodProvider(string declaringTypeName, string methodName)
+            {
+                this.declaringTypeName = declaringTypeName;
+                this.methodName = methodName;
+            }
+
+            public override Image<TPixel> GetImage()
+            {
+                this.factoryFunc ??= this.GetFactory();
+                return this.factoryFunc();
+            }
+
+            public override void Serialize(IXunitSerializationInfo info)
+            {
+                base.Serialize(info);
+
+                info.AddValue(nameof(this.declaringTypeName), this.declaringTypeName);
+                info.AddValue(nameof(this.methodName), this.methodName);
+            }
+
+            public override void Deserialize(IXunitSerializationInfo info)
+            {
+                base.Deserialize(info);
+
+                this.methodName = info.GetValue<string>(nameof(this.methodName));
+                this.declaringTypeName = info.GetValue<string>(nameof(this.declaringTypeName));
+            }
+
+            private Func<Image<TPixel>> GetFactory()
+            {
+                var declaringType = Type.GetType(this.declaringTypeName);
+                MethodInfo m = declaringType.GetMethod(this.methodName);
+                Type pixelType = typeof(TPixel);
+                Type imgType = typeof(Image<>).MakeGenericType(pixelType);
+                Type funcType = typeof(Func<>).MakeGenericType(imgType);
+                MethodInfo genericMethod = m.MakeGenericMethod(pixelType);
+                return (Func<Image<TPixel>>) genericMethod.CreateDelegate(funcType);
+            }
+        }
+    }
+}

tests/ImageSharp.Tests/TestUtilities/ImageProviders/TestImageProvider.cs

@@ -73,10 +73,11 @@ namespace SixLabors.ImageSharp.Tests
         }
 
         public static TestImageProvider<TPixel> Lambda(
-                Func<Image<TPixel>> factoryFunc,
+                string declaringTypeName,
+                string methodName,
                 MethodInfo testMethod = null,
                 PixelTypes pixelTypeOverride = PixelTypes.Undefined)
-            => new LambdaProvider(factoryFunc).Init(testMethod, pixelTypeOverride);
+            => new MemberMethodProvider(declaringTypeName, methodName).Init(testMethod, pixelTypeOverride);
 
         public static TestImageProvider<TPixel> Solid(
             int width,