Enhance Assert with Assert.Multiple

source/TestFramework/Assert.cs

@@ -287,6 +287,43 @@ public static void ThrowsException(Type exception, Action action, [CallerArgumen
             HandleFail("Assert.ThrowsException", $"No exception thrown. {exception.Name} exception was expected. {ReplaceNulls(message)}");
         }
 
+        /// <summary>
+        /// Executes multiple assertions and collects any failures encountered.
+        /// If one or more assertions fail, a <see cref="MultipleAssertionException"/> is thrown containing all the failures.
+        /// </summary>
+        /// <param name="assertions">The actions containing the assertions to execute.</param>
+        /// <exception cref="ArgumentNullException">Thrown when <paramref name="assertions"/> is null.</exception>
+        /// <exception cref="MultipleAssertionException">Thrown when one or more assertions fail.</exception>
+        public static void Multiple(params Action[] assertions)
+        {
+            if (assertions == null)
+            {
+                throw new ArgumentNullException(nameof(assertions));
+            }
+
+            Exception[] failures = new Exception[assertions.Length];
+            int failuresIndex = 0;
+
+            foreach (Action assertion in assertions)
+            {
+                try
+                {
+                    assertion();
+                }
+                catch (Exception ex)
+                {
+                    failures[failuresIndex++] = ex;
+                }
+            }
+
+            if (failuresIndex > 0)
+            {
+                throw new MultipleAssertionException(failures, failuresIndex);
+            }
+
+            return;
+        }
+
         [DoesNotReturn]
         internal static void HandleFail(string assertion, string message)
         {

source/TestFrameworkShared/MultipleAssertionException.cs

@@ -0,0 +1,51 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
+
+namespace TestFrameworkShared
+{
+    /// <summary>
+    /// Represents an exception that encapsulates multiple assertion failures.
+    /// </summary>
+    public class MultipleAssertionException : Exception
+    {
+        private readonly Exception[] _failures;
+        private readonly int _failureCount;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="MultipleAssertionException"/> class.
+        /// </summary>
+        /// <param name="failures">The array of exceptions representing assertion failures.</param>
+        /// <param name="failureCount">The number of failures in the <paramref name="failures"/> array.</param>
+        public MultipleAssertionException(Exception[] failures, int failureCount)
+            : base("One or more assertions failed.")
+        {
+            _failures = failures;
+            _failureCount = failureCount;
+
+            Console.WriteLine(ToString());
+        }
+
+        /// <summary>
+        /// Returns a string representation of the exception, including all assertion failures.
+        /// </summary>
+        /// <returns>A string describing the exception and all failures.</returns>
+        public override string ToString()
+        {
+            string message = base.ToString();
+
+            for (int i = 0; i < _failureCount; i++)
+            {
+                if(_failures[i] == null)
+                {
+                    continue;
+                }
+
+                message += "\n" + _failures[i].ToString();
+            }
+
+            return message;
+        }
+    }
+}

source/TestFrameworkShared/TestFrameworkShared.projitems

@@ -13,6 +13,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)CleanupAttribute.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)DataRowAttribute.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Helper.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)MultipleAssertionException.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)SetupAttribute.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)SkipTestException.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)TestClassAttribute.cs" />