Add comment to explain the fixture

Author: PerthCharern

test/Microsoft.OpenApi.Readers.Tests/DefaultSettingsFixture.cs

@@ -17,6 +17,9 @@ public class DefaultSettingsFixture
         /// </summary>
         public DefaultSettingsFixture()
         {
+            // We need RespectingRuntimeTypes() to ensure equivalence test works property,
+            // given that there are multiple types that can be used for the declared type OpenApiAny.
+            // Without this option, properties specific to those types would not be compared.
             AssertionOptions.AssertEquivalencyUsing(
                 o => o.AllowingInfiniteRecursion().RespectingRuntimeTypes());
         }

test/Microsoft.OpenApi.Readers.Tests/DefaultSettingsFixtureCollection.cs

@@ -1,6 +1,6 @@
 // ------------------------------------------------------------
 //  Copyright (c) Microsoft Corporation.  All rights reserved.
-//  Licensed under the MIT License (MIT). See License.txt in the repo root for license information.
+//  Licensed under the MIT License (MIT). See LICENSE in the repo root for license information.
 // ------------------------------------------------------------
 
 using Xunit;
@@ -11,7 +11,7 @@ namespace Microsoft.OpenApi.Readers.Tests
     /// Collection dummy class for <see cref="DefaultSettingsFixture"/>.
     /// </summary>
     /// <remarks>
-    /// This class is needed in xUnit framework to define collection name 
+    /// This class is needed in xUnit framework to define collection name
     /// to be used in unit test classes.
     /// </remarks>
     [CollectionDefinition("DefaultSettings")]

test/Microsoft.OpenApi.Tests/DefaultSettingsFixture.cs

@@ -17,6 +17,9 @@ public class DefaultSettingsFixture
         /// </summary>
         public DefaultSettingsFixture()
         {
+            // We need RespectingRuntimeTypes() to ensure equivalence test works property,
+            // given that there are multiple types that can be used for the declared type OpenApiAny.
+            // Without this option, properties specific to those types would not be compared.
             AssertionOptions.AssertEquivalencyUsing(
                 o => o.AllowingInfiniteRecursion().RespectingRuntimeTypes());
         }

test/Microsoft.OpenApi.Tests/DefaultSettingsFixtureCollection.cs

@@ -1,6 +1,6 @@
 // ------------------------------------------------------------
 //  Copyright (c) Microsoft Corporation.  All rights reserved.
-//  Licensed under the MIT License (MIT). See License.txt in the repo root for license information.
+//  Licensed under the MIT License (MIT). See LICENSE in the repo root for license information.
 // ------------------------------------------------------------
 
 using Xunit;
@@ -11,7 +11,7 @@ namespace Microsoft.OpenApi.Tests
     /// Collection dummy class for <see cref="DefaultSettingsFixture"/>.
     /// </summary>
     /// <remarks>
-    /// This class is needed in xUnit framework to define collection name 
+    /// This class is needed in xUnit framework to define collection name
     /// to be used in unit test classes.
     /// </remarks>
     [CollectionDefinition("DefaultSettings")]