write-library-tests

# Testing in the IgniteUI Blazor (Lite) repo Three test projects under `tests/`, two suites: | Project | Suite | What it is | |---|---|---| | `IgniteUI.Blazor.Tests` | **Unit** | xUnit + bUnit, multi-targeted `net8.0`/`net9.0`/`net10.0`; renders components in-process with a recording JS runtime — no browser | | `IgniteUI.Blazor.Lite.IntegrationTests` | **Integration** | NUnit + Playwright; one generated test fixture per component | | `IgniteUI.Blazor.Lite.TestBed` | (integration host) | Blazor app the integration tests drive; renders one component per run and sweeps its surface | ## How the suites divide the work | Behavior | Where it's tested | |---|---| | Property → rendered attribute (direct-render components) | unit: plain bUnit facts (`cut.Find(...).GetAttribute(...)`) | | **Own element and render mode** — the component renders its web component's tag as its root, with `data-ig-root` when the client renderer drives it through descriptions (Calendar, Chat, Color Picker, Combo, Date Picker, Date Range Picker, Date Time Input, Mask Input) | unit: a `<Name>_RendersCorrectElement` fact in every component's suite, `cut.Find("igc-<tag>")`; for a renderer-driven component also assert `data-ig-root` on it, since that attribute picks the client path | | Markup/child content rendering | unit: plain bUnit facts | | **Parent/child collection membership** — a child registering itself into its parent's collection and leaving again over the child's lifetime | unit: plain bUnit facts in the *parent's* suite, in a `#region Child collection lifecycle` — membership only; name resolution *off* that collection is interop behavior and stays in the contract | | Message-borne state serialization shapes | unit: `EnumSerializationTests` / `RenderingSerializationTests` | | **Interop wire behavior** — method identifiers, argument serialization + type tags, return decoding, event-handler registration/removal transmissions + JS→.NET event dispatch, `@bind-` two-way round trips, interop-borne props/data | unit: the component's `ComponentContract` — full authoring guide: [`references/interop-contracts.md`](./references/interop-contracts.md) | | `<Member>Script` parameters (JS-side handlers/providers) | unit: automated sweep (`ScriptPropTests`, all components at once; a base class is swept through the components derived from it — no per-contract entries, no integration coverage exists) | | End-to-end prop/event/method behavior against the **real web component in a real browser** | integration: the TestBed sweep | | Visual output, client-side component logic | integration / e2e — never unit | The suites overlap on purpose but answer different questions. Integration proves the full pipeline works end-to-end, but can't attribute a failure to a side of the boundary and skips everything excluded in `componentsConfig.json`. Interop contracts pin the .NET side of the wire protocol at unit speed, per member — including the members integration excludes — and tolerate different implementations through the `InteropHarness` seam (`InteropHarnessRegistry` swaps stacks per component). ## Unit suite (`tests/IgniteUI.Blazor.Tests`) ### Base classes - **`BlazorComponentTestBase`** — bUnit `BunitContext` with setup `IIgniteUIBlazor` service, a recording JS runtime (`JSRuntimeMode.Loose`; every invocation recorded) and an `Interop` harness property (an `InteropHarness`, resolved per component type via `InteropFor<TComponent>()`). Default base for suites without an interop contract. - **`ComponentWithContractTestBase<TComponent>`** — adds a declarative `ComponentContract<TComponent>`, `protected` runners (`VerifyMethodContract`/`VerifyPropContract`/`VerifyEventContract`) that the suite exposes as one-liner `[Fact]`s, and an inherited `Contract_SectionsHaveFacts` guard that fails if a non-empty contract section has no runner fact. Exactly one suite per component carries the contract; sync/async method pairs are declared together via the twin overloads. ### Running ``` dotnet test tests/IgniteUI.Blazor.Tests -f net10.0 --nologo --filter "FullyQualifiedName~<Name>Tests" ``` - Iterate on one TFM (`-f net10.0`); finish with a full run on all TFMs (drop `-f`). - Contract failure stacks carry the violated contract line as the top frame — the test UI navigates to the spec, not the shared runner. ### Conventions - Generally follow **one file per component: `<Name>Tests.cs` holds `<Name>Tests`.** A component's **child** components may share the parent's file (`SelectTests.cs` also holds `SelectItemTests`/`SelectGroupTests`/`SelectHeaderTests`; likewise Card, List, Dropdown, NavDrawer, Tabs, Stepper, TileManager, Tree, Rating, Slider) — that's the only permitted multi-class file. Cross-cutting suites (`BaseControlTests`, `*SerializationTests`, `ScriptPropTests`, `Interop*Tests`) are keyed to a class/behavior, not a component, and keep their own files. - New facts go into the existing `<Name>Tests` class; if the class carries a contract, plain bUnit facts sit alongside the contract runners in the same class. - Shared test helpers live in `ElementAssertionExtensions.cs`. - **Readable arrange/act/assert in the test beats sharing.** A little repetition across suites is fine; extract obvious repeated mechanics if needed, but ensure those are well documented and easy to grasp without breaking the flow of the test itself. - **Skips need a mechanism reason.** Bug-tracker or `componentsConfig.json` listings are not skip reasons. If a member's decode hits a gap in shared infrastructure the change doesn't own, cover it pinning current behavior and write the *correct* assertion commented out under a `// TODO:` explaining the gap — ready to uncomment when fixed. A gap in a component under construction is a bug to fix, not to pin — see the two authoring modes in the interop reference. - Components are `partial` — the generated `src/components/Blazor/<Name>.cs` is not the whole class; always check `src/componentsBase/WebInputs/<Name>.cs` for hand-written extensions before drawing conclusions. - Formatting: only `dotnet format whitespace --folder` is safe in this repo — a full `dotnet format` writes conflict markers into multi-targeted sources. ## Integration suite (Playwright + TestBed) One generic NUnit test per component (`ComponentTest`, fixture-sourced from the TestBed's component list): it boots the TestBed app (in-memory by default), calls the browser-side `renderComponent('<IgbName>')`, and asserts `getErrors()` returns nothing. The real work happens inside the TestBed (`Components/Pages/Home.razor`): a **reflection-driven sweep** over the component's public surface — - **`TestProps`**: sets each `[Parameter]` server-side with generated sample values and compares against the live web component's DOM property in the browser (`TestUtil.PropertyValuesAreEqual`, client value via `stringifyObject`). - **`TestEvents`**: dispatches synthetic events against the web component and verifies the bound .NET callbacks fire. - **Method spies** (`spyOnMethod`/`checkOnSpy` in `wwwroot/app.js`): invoking the .NET API must call the matching web-component method with the right args/result. **Async methods only** — the sweep filters to `*Async` and also excludes `Get*Async` getters; sync variants can't run on the Server-hosted TestBed (no in-process JS runtime), so sync variants, getters, and `<Member>Script` params have no integration coverage — the unit suite is their only net. **`componentsConfig.json`** (in the TestBed project) gates the sweep per component: `ExcludedProps`, `ExcludedEvents`, `DependantProps`/`DependantMethods` — each entry usually cites a BUG number or a shape the generic sweep can't model. An excluded member has **no integration coverage at all** — treat those as *higher* priority for the unit interop contract, never as members to skip there too. ### Running - One-time: build, then install browsers — `pwsh tests/IgniteUI.Blazor.Lite.IntegrationTests/bin/Debug/net<version>/playwright.ps1 install chromium`. - `dotnet test tests/IgniteUI.Blazor.Lite.IntegrationTests` (or per component from the Test Explorer — fixtures are named by component). - `.runsettings` knobs: headless off for local debugging; `useInMemoryClient: false` to run against your own `dotnet run` instance of the TestBed. - Full setup details: [tests/IgniteUI.Blazor.Lite.IntegrationTests/README.md](../../../tests/IgniteUI.Blazor.Lite.IntegrationTests/README.md). ## Adding coverage for a new component — checklist 1. Unit suite: a `<Name>_RendersCorrectElement` fact (own element, plus `data-ig-root` if renderer-driven), bUnit facts for rendered attributes/markup; if the component has an interop surface (it sends interop invocations or registers JS-originated event handlers — the reference explains how to identify these per stack), add a `ComponentContract` per [`references/interop-contracts.md`](./references/interop-contracts.md). For a brand-new component this works TDD-style: author the contract first from the intended API following the library's conventions; the contract doubles as the API design record (spec mode in the reference). 2. If it is a parent that collects children, or a child that registers with a parent, exercise that membership **over the child's lifetime**, not just at first render: the children are the collection in order, a disposed child leaves it, all disposed empties it. Keep these facts to membership and asserting resolution that are covered by the interop contract. 3. Integration: the sweep picks the component up automatically; add `componentsConfig.json` entries only for members the generic sweep genuinely cannot model (cite why), and mirror each exclusion with unit contract coverage. 4. Verify: unit full-suite on all TFMs, plus the component's integration fixture.