blazor-unit-testing

# Blazor Unit Testing Agent tests Blazor components with bUnit and the repository's established .NET test runner. ## When to Use | Condition | Use | |---|---| | User requests unit tests for a `.razor` component | Use this skill | | Component behavior depends on parameters, cascading values, or events | Use this skill | | A Blazor component needs coverage for rendering, validation, or state changes | Use this skill | ## When Not to Use | Condition | Route | |---|---| | The test drives a real browser or user journey | Use `blazor-ui-testing` | | The target is a pure service or view model | Use `xunit-test-generation` or `mstest-test-authoring` | | The task selects a Blazor hosting model | Use `blazor-patterns` | ## Required Inputs | Input | Required | Description | |---|---|---| | Component | Yes | Agent identifies the component, parameters, event callbacks, and render mode. | | Behavior | Yes | Agent identifies the visible output, state transition, or validation outcome. | | Test project | Yes | Agent identifies the bUnit project and its runner. | | Service dependencies | No | Agent provides deterministic registrations or focused substitutes. | ## Workflow | Step | Agent action | Test | Pass | |---|---|---|---| | 1 | Agent reads the component and neighboring bUnit tests. | Inspect markup, code-behind, project references, and fixtures. | Test setup matches local conventions. | | 2 | Agent configures only required services, cascading values, authentication state, and JS interop. | Review the test context registrations. | Setup stays deterministic and minimal. | | 3 | Agent renders the component with representative parameters. | Render through bUnit and inspect the DOM. | Initial markup matches the intended contract. | | 4 | Agent exercises events, forms, validation, and state updates. | Trigger the same interaction through semantic element or component APIs. | Visible output and callbacks prove the behavior. | | 5 | Agent covers one edge case and one failure or validation path. | Run targeted tests. | Invalid or boundary behavior remains explicit. | ## Component Test Matrix | Surface | Test | Pass | |---|---|---| | Parameters | Render with required, optional, and boundary values. | Output reflects each supported parameter state. | | Events | Trigger clicks, input, submit, and callback events. | Expected callback payload and rendered state are asserted. | | Forms | Submit valid and invalid models. | Validation messages and submission behavior are asserted. | | Cascading state | Provide the required cascading value or authentication state. | Component responds without hidden global state. | | JS interop | Configure only expected calls and arguments. | Browser-bound behavior stays verifiable without a real browser. | | Async rendering | Await scheduled renders and task completion. | Tests do not rely on arbitrary delays. | ## Verification Checklist - [ ] bUnit renders the target component successfully. - [ ] Tests assert semantic markup or component state instead of CSS-only details. - [ ] Event callbacks, validation, and async state changes have coverage where applicable. - [ ] Authentication and cascading state use deterministic test setup. - [ ] Targeted tests pass in the repository's existing runner. ## Common Pitfalls | Pitfall | Agent fix | |---|---| | Tests assert the entire generated HTML string | Query stable semantic elements and assert the relevant contract. | | Component setup registers every application service | Register only dependencies used by the rendered path. | | JS interop calls remain unverified | Assert expected identifiers, arguments, and invocation count. | | Async work is hidden behind sleeps | Await the component task or bUnit render completion. |