Testing Strategy

ManagedCode.Storage uses xUnit + Shouldly and aims to verify storage behaviour through realistic flows (upload/download/list/delete/metadata) with minimal mocking.

Test Project

• Primary suite: Tests/ManagedCode.Storage.Tests/ManagedCode.Storage.Tests.csproj

Suite Map

flowchart TD
  Tests[ManagedCode.Storage.Tests] --> Core[Core helpers + invariants]
  Tests --> Providers[Provider suites]
  Tests --> AspNet[ASP.NET controllers + SignalR]
  Tests --> Vfs[VFS suites]

  Providers --> Containers["Testcontainers (Azurite/LocalStack/FakeGcsServer/SFTP)"]
  Providers --> CloudDrive["CloudDrive (Graph/Drive/Dropbox)"]
  CloudDrive --> HttpFakes[HttpMessageHandler fakes wired into official SDK clients]

Structure

Tests are grouped by “surface” and provider:

• Tests/ManagedCode.Storage.Tests/Core/ — ManagedCode.Storage.Core behaviour (helpers, options, invariants)
• Tests/ManagedCode.Storage.Tests/VirtualFileSystem/ — VFS behaviour and fixtures
• Tests/ManagedCode.Storage.Tests/Storages/*/ — provider suites (Azure/AWS/GCS/Browser/FileSystem/Sftp/CloudDrive/CloudKit)
• Tests/ManagedCode.Storage.Tests/AspNetTests/ — ASP.NET controllers + SignalR flows (end-to-end via in-process test host)
• Tests/ManagedCode.Storage.BrowserServerHost/ — minimal interactive Blazor Server host used for real browser verification of IndexedDB metadata + OPFS payload flows over server-side JS interop
• Tests/ManagedCode.Storage.BrowserWasmHost/ — minimal standalone Blazor WebAssembly host used for real browser verification of browser storage flows with IndexedDB metadata and OPFS payloads
• Tests/ManagedCode.Storage.Tests/Common/ — shared test utilities, Testcontainers helpers, test app host

External Dependencies

Where possible, tests run without real cloud accounts:

• Azure/AWS/GCS/SFTP suites use Testcontainers (Azurite, LocalStack, FakeGcsServer, SFTP container).
• The LocalStack-backed AWS and Orleans flows are pinned to localstack/localstack:4.14.0 because the end-of-March 2026 latest image became auth-gated and is no longer safe for anonymous CI runs.
• Browser-local coverage uses Playwright against Tests/ManagedCode.Storage.BrowserServerHost/ and Tests/ManagedCode.Storage.BrowserWasmHost/ so ManagedCode.Storage.Browser is exercised through real Chromium flows with IndexedDB metadata and OPFS payloads in both Interactive Server and standalone WASM modes.
• Those same hosts also wire ManagedCode.Storage.VirtualFileSystem over the browser provider, so browser VFS write, read, move, delete, large-file, small-file overwrite, and multi-tab concurrency flows are verified end to end in the browser rather than through in-process fakes.
• The Interactive Server host explicitly raises HubOptions.MaximumReceiveMessageSize so browser-to-server chunk reads can exceed the default 32 KB SignalR limit during large-stream verification.
• CloudDrive suites (OneDrive/Google Drive/Dropbox) use HttpMessageHandler-based fakes wired into the official SDK clients, asserting real behaviour over HTTP without hitting the network.

Categories

Some tests are marked as “large file” to validate streaming behaviour:

• [Trait("Category", "LargeFile")]
• Browser-hosted stress flows also carry [Trait("Category", "BrowserStress")].

Run the default fast suite:

dotnet test Tests/ManagedCode.Storage.Tests/ManagedCode.Storage.Tests.csproj --configuration Release --filter "Category!=BrowserStress"

Install the Playwright browser for the browser-local tests:

dotnet tool restore
dotnet build Tests/ManagedCode.Storage.Tests/ManagedCode.Storage.Tests.csproj --configuration Release
dotnet playwright -p Tests/ManagedCode.Storage.Tests/ManagedCode.Storage.Tests.csproj install chromium

Skip large-file tests when iterating:

dotnet test Tests/ManagedCode.Storage.Tests/ManagedCode.Storage.Tests.csproj --configuration Release --filter "Category!=LargeFile"

Skip the hosted-browser stress lane while still running the default fast browser coverage:

dotnet test Tests/ManagedCode.Storage.Tests/ManagedCode.Storage.Tests.csproj --configuration Release --filter "Category!=BrowserStress"

Run only the hosted-browser stress lane locally when you explicitly need it:

dotnet test Tests/ManagedCode.Storage.Tests/ManagedCode.Storage.Tests.csproj --configuration Release --filter "Category=BrowserStress"

Tiered browser large-file coverage now works like this:

• default build-and-test still includes a real end-to-end browser large-file lane, but at a fast 128 MiB size so Storage.GetStreamAsync stays covered in the normal PR path
• Category=BrowserStress runs a heavier 256 MiB cross-page integrity check for both Interactive Server and WASM, using a worker-side OPFS digest so the stress lane proves persistence without paying the old full .NET read-back cost
• the browser-stress CI job and the Release workflow both run that explicit stress lane automatically

The earlier 1 GiB browser target was removed from automated CI because Chromium-backed WASM verification hit an unstable OPFS write boundary around 512 MiB, so 256 MiB became the stable automated stress target.

Quality Rules

• Each test must assert concrete, observable behaviour (state/output/errors/side-effects).
• Mocks/fakes are allowed only for external systems that cannot reasonably run in tests; the fake must match the official API surface (paths, status codes, payload shapes).
• Do not weaken or delete tests to make them pass; fix the behaviour instead.