feat: add Playwright test harness with SSR and CSR support#7428
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feat: add Playwright test harness with SSR and CSR support#7428
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janechu
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Apr 11, 2026
| test.describe("Button", () => { | ||
| test.use({ tagName: "my-button", innerHTML: "Click me" }); | ||
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| test("should render", async ({ fastPage }) => { |
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Since this is specifically from the @microsoft/fast-test-harness package, could this just be page instead of fastPage?
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page is already the name of the built-in Playwright page fixture: https://playwright.dev/docs/test-fixtures#built-in-fixtures
janechu
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Apr 11, 2026
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Pull Request
📖 Description
Adds
@microsoft/fast-test-harness, a new Playwright testing harness package for FAST web components. The harness provides shared fixtures for both client-side rendering (CSR) and server-side rendering (SSR) test workflows, a custom Express + Vite dev server, SSR rendering utilities, and support for custom assertions.This package is intended to be consumed by component packages in the monorepo (and downstream projects like MAI) to standardize how Playwright tests are authored and run against FAST-based web components.
👩💻 Reviewer Notes
privateand is not published to npm.@microsoft/fast-htmland@microsoft/fast-build.server.mjsentrypoint uses Express 5 and Vite'screateServerAPI to handle both CSR page serving and SSR fixture generation in a single process.📑 Test Plan
This package provides test infrastructure rather than component behavior. Validation will come from downstream adoption in component packages that use the harness fixtures. No Playwright tests are included in this package itself.
✅ Checklist
General
$ npm run change⏭ Next Steps
wasm-renderer.tsmodule wraps the Rust-basedfast-buildWASM renderer for SSR template compilation. This may be extracted or refined asfast-buildstabilizes.