Cherry pick 27542

#27542

Author: TanayParikh

src/Tests/Microsoft.NET.Sdk.Razor.Tests/AspNetSdkBaselineTest.cs

@@ -356,8 +356,35 @@ internal void AssertManifest(
                     .Should()
                     .BeEquivalentTo(expected.ReferencedProjectsConfiguration.OrderBy(cm => cm.Identity));
                 manifest.DiscoveryPatterns.OrderBy(dp => dp.Name).ShouldBeEquivalentTo(expected.DiscoveryPatterns.OrderBy(dp => dp.Name));
-                manifest.Assets.OrderBy(a => a.BasePath).ThenBy(a => a.RelativePath).ThenBy(a => a.AssetKind)
-                    .ShouldBeEquivalentTo(expected.Assets.OrderBy(a => a.BasePath).ThenBy(a => a.RelativePath).ThenBy(a => a.AssetKind));
+                var manifestAssets = manifest.Assets.OrderBy(a => a.BasePath).ThenBy(a => a.RelativePath).ThenBy(a => a.AssetKind);
+                var expectedAssets = expected.Assets.OrderBy(a => a.BasePath).ThenBy(a => a.RelativePath).ThenBy(a => a.AssetKind);
+                
+                manifestAssets.ShouldBeEquivalentTo(expectedAssets, AssetDifferencesDetails(manifestAssets, expectedAssets));
+
+                static string AssetDifferencesDetails(IEnumerable<StaticWebAsset> manifestAssets, IEnumerable<StaticWebAsset> expectedAssets)
+                {
+                    var missingAssets = expectedAssets.Except(manifestAssets);
+                    var unexpectedAssets = manifestAssets.Except(expectedAssets);
+
+                    var differences = new List<string>();
+
+                    if (missingAssets.Any())
+                    {
+                        differences.Add($"The following expected assets weren't found in the manifest {string.Join(", ", missingAssets.Select(a => a.Identity))}.");
+                    }
+
+                    if (unexpectedAssets.Any())
+                    {
+                        differences.Add($"The following additional unexpected assets were found in the manifest {string.Join(", ", unexpectedAssets.Select(a => a.Identity))}.");
+                    }
+
+                    if (differences.Any())
+                    {
+                        differences.Add("If the difference in baselines is expected, please re-generate the baselines using the src/RazorSdk/update-test-baselines.ps1 script.");
+                    }
+
+                    return string.Join(Environment.NewLine, differences);
+                }
             }
             else
             {