Try to setup vitest integration

packages/alfa-vitest/config/api-extractor.json

@@ -0,0 +1,5 @@
+{
+  "$schema": "https://developer.microsoft.com/json-schemas/api-extractor/v7/api-extractor.schema.json",
+  "extends": "../../../config/api-extractor.json",
+  "mainEntryPointFilePath": "<projectFolder>/dist/index.d.ts"
+}

packages/alfa-vitest/package.json

@@ -0,0 +1,52 @@
+{
+  "$schema": "http://json.schemastore.org/package",
+  "name": "@siteimprove/alfa-vitest",
+  "homepage": "https://alfa.siteimprove.com",
+  "version": "0.74.2",
+  "license": "MIT",
+  "description": "Assertion integrations for the Vitest testing framework",
+  "repository": {
+    "type": "git",
+    "url": "github:Siteimprove/alfa-integrations",
+    "directory": "packages/alfa-vitest"
+  },
+  "bugs": "https://github.com/siteimprove/alfa/issues",
+  "engines": {
+    "node": ">=20.0.0"
+  },
+  "type": "module",
+  "main": "dist/index.js",
+  "types": "dist/index.d.ts",
+  "files": [
+    "dist/**/*.js",
+    "dist/**/*.d.ts"
+  ],
+  "scripts": {
+    "test": "vitest"
+  },
+  "dependencies": {
+    "@siteimprove/alfa-act": "^0.93.8",
+    "@siteimprove/alfa-assert": "workspace:^",
+    "@siteimprove/alfa-future": "^0.93.8",
+    "@siteimprove/alfa-hash": "^0.93.8",
+    "@siteimprove/alfa-mapper": "^0.93.8",
+    "vitest": "^2.1.4"
+  },
+  "peerDependencies": {
+    "@siteimprove/alfa-act": "^0.93.8",
+    "@siteimprove/alfa-future": "^0.93.8",
+    "@siteimprove/alfa-hash": "^0.93.8",
+    "@siteimprove/alfa-mapper": "^0.93.8"
+  },
+  "publishConfig": {
+    "access": "public",
+    "registry": "https://npm.pkg.github.com/"
+  },
+  "devDependencies": {
+    "@siteimprove/alfa-device": "^0.93.8",
+    "@siteimprove/alfa-dom": "^0.93.8",
+    "@siteimprove/alfa-http": "^0.93.8",
+    "@siteimprove/alfa-rules": "^0.93.8",
+    "@siteimprove/alfa-web": "^0.93.8"
+  }
+}

packages/alfa-vitest/src/index.ts

@@ -0,0 +1 @@
+export * from "./vitest.js";

packages/alfa-vitest/src/tsconfig.json

@@ -0,0 +1,7 @@
+{
+  "$schema": "http://json.schemastore.org/tsconfig",
+  "extends": "../tsconfig.json",
+  "compilerOptions": { "outDir": "../dist" },
+  "files": ["./index.ts", "./vitest.ts"],
+  "references": [{ "path": "../../alfa-assert" }]
+}

packages/alfa-vitest/src/vitest.ts

@@ -0,0 +1,57 @@
+import type { Question, Rule } from "@siteimprove/alfa-act";
+import type { Handler } from "@siteimprove/alfa-assert";
+import { Asserter } from "@siteimprove/alfa-assert";
+import type { Future } from "@siteimprove/alfa-future";
+import type { Hashable } from "@siteimprove/alfa-hash";
+import type { Mapper } from "@siteimprove/alfa-mapper";
+
+import { expect } from "vitest";
+
+interface CustomMatchers<R = unknown> {
+  toBeAccessible: () => R;
+}
+
+declare module "vitest" {
+  interface Assertion<T = any> extends CustomMatchers<T> {}
+  interface AsymmetricMatchersContaining extends CustomMatchers {}
+}
+
+/**
+ * @public
+ */
+export namespace Vitest {
+  export function createPlugin<
+    I,
+    J,
+    T extends Hashable,
+    Q extends Question.Metadata = {},
+    S = T
+  >(
+    transform: Mapper<I, Future.Maybe<J>>,
+    rules: Iterable<Rule<J, T, Q, S>>,
+    handlers: Iterable<Handler<J, T, Q, S>> = [],
+    options: Asserter.Options<J, T, Q, S> = {}
+  ): void {
+    const asserter = Asserter.of(rules, handlers, options);
+
+    expect.extend({
+      async toBeAccessible(value: I) {
+        const input = await transform(value);
+
+        const result = await asserter.expect(input).to.be.accessible();
+
+        const message = result.isOk() ? result.get() : result.getErrUnsafe();
+
+        return {
+          pass: result.isOk(),
+          message: () =>
+            this.utils.matcherHint("toBeAccessible", "received", "", {
+              isNot: this.isNot,
+            }) +
+            " but " +
+            message,
+        };
+      },
+    });
+  }
+}

packages/alfa-vitest/test/tsconfig.json

@@ -0,0 +1,12 @@
+{
+  "$schema": "http://json.schemastore.org/tsconfig",
+  "extends": "../tsconfig.json",
+  "compilerOptions": {
+    "outDir": ".",
+    "jsx": "react-jsx",
+    "jsxImportSource": "@siteimprove/alfa-dom",
+    "types": ["vitest"]
+  },
+  "files": ["./vitest.spec.tsx"],
+  "references": [{ "path": "../src" }]
+}

packages/alfa-vitest/test/vitest.spec.tsx

@@ -0,0 +1,37 @@
+import { Device } from "@siteimprove/alfa-device";
+import { h } from "@siteimprove/alfa-dom";
+import { Request, Response } from "@siteimprove/alfa-http";
+import { Rules } from "@siteimprove/alfa-rules";
+import { Page } from "@siteimprove/alfa-web";
+
+import { expect } from "vitest";
+
+import { Vitest } from "../dist/vitest.js";
+
+Vitest.createPlugin((page: Page) => page, [Rules.get("R12").getUnsafe()]);
+
+describe(".createPlugin adds a .toBeAccessible method", () => {
+  const page = Page.of(
+    Request.empty(),
+    Response.empty(),
+    h.document([<button>Hello World</button>]),
+    Device.standard()
+  );
+
+  it("should have a .toBeAccessible method", async () => {
+    await expect(page).toBeAccessible();
+  });
+});
+
+describe(".createPlugin adds a .not.toBeAccessible method", () => {
+  const page = Page.of(
+    Request.empty(),
+    Response.empty(),
+    h.document([<button></button>]),
+    Device.standard()
+  );
+
+  it("should have a .not.toBeAccessible method", async () => {
+    await expect(page).not.toBeAccessible();
+  });
+});

packages/alfa-vitest/tsconfig.json

@@ -0,0 +1,5 @@
+{
+  "$schema": "http://json.schemastore.org/tsconfig",
+  "extends": "../tsconfig.json",
+  "references": [{ "path": "./src" }, { "path": "./test" }]
+}

packages/tsconfig.json

@@ -28,6 +28,7 @@
     { "path": "alfa-selenium" },
     { "path": "alfa-test-utils" },
     { "path": "alfa-unexpected" },
+    { "path": "alfa-vitest" },
     { "path": "alfa-vue" },
     { "path": "alfa-webdriver" }
   ]