[StaticWebAssets] Add MAUI Blazor Hybrid + BlazorWebView regression test (dotnet/sdk#54779)

[javiercn]

Summary

Adds integration coverage for the MAUI Blazor Hybrid scenario from #54779: an app (Microsoft.NET.Sdk.Razor) that references a Razor class library and the BlazorWebView package, where the package contributes a fallback _framework/blazor.modules.json.

This is test-only — there is no SDK product code change. The actual fix belongs upstream in dotnet/aspnetcore (tracked by dotnet/aspnetcore#67374); this PR locks in coverage so the scenario keeps working in the SDK.

What the test covers

test/TestAssets/TestProjects/MauiBlazorHybridWebView packs a simulated BlazorWebView package that models blazor.modules.json as a Framework asset (StaticWebAssetFrameworkPattern), mirroring how Microsoft.AspNetCore.Components.WebAssembly ships its framework assets. The asset encodes the idiomatic behavior: the manifest is materialized once into the consuming project at build, becomes an ordinary project asset, and the app's own generated manifest wins — with the package manifest serving as the fallback when the app has no JS modules. The .csproj/.props carry comments pointing at the real aspnetcore/maui sources and the tracking issues.

MauiBlazorHybridWebViewIntegrationTest tracks both outcomes of the scenario:

1. Publish_FrameworkModulesAsset_AppHasModules_AppManifestWins — the app contributes JS modules, so a single _framework/blazor.modules.json endpoint is produced and the app's generated (Computed) manifest wins (the package fallback is not used).
2. Publish_FrameworkModulesAsset_NoAppModules_UsesMaterializedPackageFallback — with no app JS modules, the materialized package manifest (Discovered) is the one that is served.

In addition to endpoint/source selection, the tests now also validate the published _framework/blazor.modules.json contents:

• app-manifest-wins case contains the app + RCL JS module entries;
• package-fallback case contains the expected empty array ([]).

The package is consumed as a real PackageReference (packed to $(AspNetTestPackageSource), restored via IsolatedNuGetPackageFolderAspNetSdkBaselineTest) so publish-time framework-asset materialization is exercised faithfully — a project-to-project reference would not materialize framework assets at publish.

Validation

Microsoft.NET.Sdk.StaticWebAssets.Tests  Total: 2, Errors: 0, Failed: 0, Skipped: 0

Related

• [Preview 6 regression] GenerateStaticWebAssetEndpointsManifest throws Sequence contains more than one element when a MAUI Blazor Hybrid project references a Razor class library and the BlazorWebView package #54779 — the publish-time Sequence contains more than one element crash this scenario regressed into.
• BlazorWebView: model blazor.modules.json as a Framework asset (fixes publish-time Sequence contains more than one element in MAUI Blazor Hybrid + RCL) aspnetcore#67374 — the idiomatic package-side fix.
• Revert StaticWebAssets gallery-sample workaround once dotnet/sdk#54779 is fixed maui#35953 — the MAUI gallery regression (worked around with JSModulesEnabled=false).

[Copilot]

Pull request overview

Adds an integration regression test for the MAUI Blazor Hybrid + BlazorWebView scenario from #54779 by introducing a new test asset that simulates the package/app/library shape and a corresponding dotnet publish-driven test that asserts the failure and the fixed behavior.

Changes:

• Adds a new MauiBlazorHybridWebView test asset containing a simulated app, Razor class library, and a packable “BlazorWebViewPackage” that can author the fallback modules manifest via two modes (group vs framework asset).
• Adds MauiBlazorHybridWebViewIntegrationTest covering the regression (expected failure) and the fixed behavior (publish succeeds and selects the correct _framework/blazor.modules.json endpoint).
• Introduces minimal JS/CSS/Razor content to ensure JS module manifest generation and static web asset flows are exercised.

Reviewed changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
test/TestAssets/TestProjects/MauiBlazorHybridWebView/MauiRazorClassLibrary/wwwroot/MauiRazorClassLibrary.lib.module.js	Provides an RCL JS module input to trigger JS module manifest generation.
test/TestAssets/TestProjects/MauiBlazorHybridWebView/MauiRazorClassLibrary/wwwroot/css/rcl.css	Adds RCL static web asset content for realism.
test/TestAssets/TestProjects/MauiBlazorHybridWebView/MauiRazorClassLibrary/MauiRazorClassLibrary.csproj	Defines the Razor class library used by the simulated app.
test/TestAssets/TestProjects/MauiBlazorHybridWebView/MauiRazorClassLibrary/Component1.razor.css	Adds scoped CSS to more closely match real RCL usage.
test/TestAssets/TestProjects/MauiBlazorHybridWebView/MauiRazorClassLibrary/Component1.razor	Adds a simple component to ensure the project is a Razor class library.
test/TestAssets/TestProjects/MauiBlazorHybridWebView/MauiBlazorApp/wwwroot/MauiBlazorApp.lib.module.js	Provides app-side JS module input to produce an app-generated modules manifest.
test/TestAssets/TestProjects/MauiBlazorHybridWebView/MauiBlazorApp/MauiBlazorApp.csproj	Simulates the MAUI hybrid app shape (Root static web assets mode + package + P2P reference).
test/TestAssets/TestProjects/MauiBlazorHybridWebView/MauiBlazorApp/Class1.cs	Minimal compile-time marker for the simulated app project.
test/TestAssets/TestProjects/MauiBlazorHybridWebView/BlazorWebViewPackage/wwwroot/_framework/blazor.webview.js	Simulated framework script shipped by the BlazorWebView-like package.
test/TestAssets/TestProjects/MauiBlazorHybridWebView/BlazorWebViewPackage/wwwroot/_framework/blazor.modules.json	Simulated fallback blazor.modules.json shipped by the package.
test/TestAssets/TestProjects/MauiBlazorHybridWebView/BlazorWebViewPackage/Class1.cs	Minimal compile-time marker for the simulated package project.
test/TestAssets/TestProjects/MauiBlazorHybridWebView/BlazorWebViewPackage/build/BlazorWebViewPackage.props	Implements the two authoring modes (group vs framework asset) to reproduce and validate the regression/fix behavior.
test/TestAssets/TestProjects/MauiBlazorHybridWebView/BlazorWebViewPackage/BlazorWebViewPackage.csproj	Packs the simulated package and toggles framework-asset modeling via StaticWebAssetFrameworkPattern.
test/Microsoft.NET.Sdk.StaticWebAssets.Tests/MauiBlazorHybridWebViewIntegrationTest.cs	New integration test asserting the regression failure and validating the fixed behavior and fallback behavior.

[javiercn]

Tests should also validate the contents of the modules.json file for correctness

[javiercn]

@copilot chop chop

[Copilot]

Addressed in ab5a12d. The integration tests now assert _framework/blazor.modules.json content for both scenarios: app+RCL modules are present when the app manifest wins, and the fallback manifest is empty when app modules are removed.