Testing

csls uses MSTest on Microsoft Testing Platform. Test methods run in parallel, while fixtures that launch costly external programs use bounded shared leases. Run tests without suppressing the build step so source and analyzer errors cannot hide behind an older test binary.

dotnet test --solution Csls.slnx
dotnet test --project tests/Csls.Tests/Csls.Tests.csproj -- --filter "Name~Completion"

Real behavior

Language-server tests start the real managed worker and drive production standard streams with StreamJsonRpc. They create temporary SDK projects, solutions, Razor projects, file-based apps, Unity layouts, and legacy project shapes, then assert on Roslyn results and protocol payloads. MCP tests use the official client and server transport. Control tests use real Unix domain sockets.

Multi-target coverage loads an SDK project with several target frameworks and verifies the selected Roslyn flavor through a real hover request. Diagnostic cache coverage changes one project and confirms that an unrelated project stays unchanged.

Tests do not replace Roslyn, MSBuild, the file system, processes, clocks, sockets, or edit application with mocking libraries. Malformed wire data is constructed only when the behavior under test is input rejection.

The language suite covers advertised capabilities, initialization, cancellation, workspace generations, file operations, diagnostics, semantic edits, CLI commands, MCP tools, control resources, package workers, and shutdown. Parity cases keep ported behavior executable without publishing private backlog references. Watched-file coverage changes a closed source file on disk through the real LSP worker, observes the diagnostic refresh request, and verifies that an open dependent document updates without restarting the editor.

Editor sessions

Fresh, GNU Emacs with Eglot, Helix, and Neovim run in real Hex1b terminals. The packaged VS Code extension runs in desktop and remote extension hosts. Its browser extension and WebAssembly server run in Chromium, Firefox, and WebKit. Every VS Code host executes the same hover, completion, definition, semantic token, configurable inlay hint, diagnostics, formatting, rename, code action, file synchronization, and restart contract. Zed runs with the csls extension. Tests wait for visible editor or protocol state instead of fixed delays.

Provisioners are .NET file-based apps. Each one selects the current pinned release for the host operating system and architecture, verifies its digest, extracts it under artifacts/tools, and reuses it on later runs.

dotnet run --file scripts/Provision-Fresh.cs
dotnet run --file scripts/Provision-Emacs.cs
dotnet run --file scripts/Provision-Helix.cs
dotnet run --file scripts/Provision-Neovim.cs
dotnet run --file scripts/Provision-VsCode.cs
dotnet run --file scripts/Provision-VsCodeRemoteServer.cs
dotnet run --file scripts/Provision-Zed.cs

Pass --with-web-browsers to the VS Code provisioner to install the pinned Chromium, Firefox, and WebKit builds. Linux also needs the browser and display packages installed by Install-GraphicalEditorTestPrerequisites.cs.

Legacy workspace jobs run old project files without reference-assembly packages. Windows uses the Visual Studio or Build Tools MSBuild host, while Linux and macOS use Mono MSBuild. The test fails unless framework references and semantic results come from the platform host. Run its prerequisite with:

dotnet run --file scripts/Provision-LegacyBuildHost.cs

Debugging a failing protocol test

$/csharp/debugInfo is the first diagnostic source. A phase of Uninitialized means initialization did not complete. Empty folders mean no workspace was loaded. Request statistics show whether a notification entered and completed its handler.

Server logs are written to standard error. A focused test can forward that stream while it runs, but temporary diagnostic output must not remain in product code. Use the correlation identifier from debug information, the dashboard, or a trace to follow cancellation and scheduling.

Repository gates

The test matrix covers Windows, Linux, macOS, x64, and Arm64. Dedicated jobs verify Visual Studio Build Tools and Mono project loading. Additional package jobs cover Windows x86 and Linux musl. The dev-container job builds and scans the same container developers use. Repository policy rejects warning suppressions, ignored tests, missing XML documentation, multiple types in one file, unpinned workflow actions, and dependencies outside the approved product boundary.

Test results are written as TRX artifacts. MSBuild failures should be rerun with a binary logger so evaluation, SDK selection, and project imports can be inspected.