Extracted extension method for better readability in endpoint routing (#326)

Author: ivaylokenov

src/MyTested.AspNetCore.Mvc.Abstractions/Internal/Application/ApplicationBuilderMock.cs

@@ -3,7 +3,6 @@
     using System;
     using System.Collections.Generic;
     using System.Linq;
-    using System.Reflection;
     using System.Threading.Tasks;
     using Microsoft.AspNetCore.Builder;
     using Microsoft.AspNetCore.Http;
@@ -132,12 +131,7 @@ private void CheckForEndpointRouting(IServiceProvider serviceProvider)
 
         private void ExtractEndpointRoutes(Func<RequestDelegate, RequestDelegate> middleware)
         {
-            var middlewareTypeField = middleware
-               .Target
-               .GetType()
-               .GetTypeInfo()
-               .DeclaredFields
-               .FirstOrDefault(m => m.Name == "middleware");
+            var middlewareTypeField = middleware.GetTargetField("middleware");
 
             if (!(middlewareTypeField?.GetValue(middleware.Target) is Type middlewareType)
                 || middlewareType.Name != "EndpointMiddleware")
@@ -232,12 +226,7 @@ private void ExtractEndpointRoutes(Func<RequestDelegate, RequestDelegate> middle
 
         private void ExtractLegacyRoutes(Func<RequestDelegate, RequestDelegate> middleware)
         {
-            var middlewareArguments = middleware
-               .Target
-               .GetType()
-               .GetTypeInfo()
-               .DeclaredFields
-               .FirstOrDefault(m => m.Name == "args");
+            var middlewareArguments = middleware.GetTargetField("args");
 
             if (middlewareArguments?.GetValue(middleware.Target) is object[] argumentsValues)
             {

src/MyTested.AspNetCore.Mvc.Abstractions/Utilities/Extensions/FuncExtensions.cs

@@ -0,0 +1,19 @@
+namespace MyTested.AspNetCore.Mvc.Utilities.Extensions
+{
+    using System;
+    using System.Linq;
+    using System.Reflection;
+
+    public static class FuncExtensions
+    {
+        public static FieldInfo GetTargetField<T, TResult>(
+            this Func<T, TResult> func,
+            string fieldName)
+            => func
+               .Target
+               .GetType()
+               .GetTypeInfo()
+               .DeclaredFields
+               .FirstOrDefault(m => m.Name == fieldName);
+    }
+}