feat: add node-test-floating-promises example

Author: JoshuaKGoldberg

Diff for: packages/node-test-floating-promises/README.md

@@ -0,0 +1,25 @@
+# Example: `node:test` and Floating Promise Detection
+
+An example of using [`node:test`](https://nodejs.org/api/test.html) along with [`@typescript-eslint/no-floating-promises` rule](https://typescript-eslint.io/rules/no-floating-promises) enabled.
+It uses the [`allowForKnownSafeCalls` rule option](https://typescript-eslint.io/rules/no-floating-promises/#allowforknownsafecalls) to not report on calls to `test()`.
+
+## Setup
+
+```shell
+npm i
+```
+
+## Usage
+
+```shell
+npm run lint
+```
+
+There should be no lint reports.
+
+If you remove the `allowForKnownSafeCalls` option from `eslint.config.js`, there will be:
+
+```plaintext
+.../index.test.ts
+  4:1  error  Promises must be awaited, end with a call to .catch, end with a call to .then with a rejection handler or be explicitly marked as ignored with the `void` operator  @typescript-eslint/no-floating-promises
+```

Diff for: packages/node-test-floating-promises/eslint.config.js

@@ -0,0 +1,27 @@
+// @ts-check
+
+import eslint from "@eslint/js";
+import tseslint from "typescript-eslint";
+
+export default tseslint.config(
+  eslint.configs.recommended,
+  tseslint.configs.recommendedTypeChecked,
+  {
+    languageOptions: {
+      parserOptions: {
+        projectService: {
+          allowDefaultProject: ['*.config.*']
+        },
+      },
+    },
+    rules: {
+      "@typescript-eslint/no-floating-promises": [
+        "error", {
+          "allowForKnownSafeCalls": [
+            { "from": "package", "name": "test", "package": "node:test" }
+          ]
+        }
+      ]
+    }
+  }
+);

Diff for: packages/node-test-floating-promises/index.test.ts

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+import { strict as assert } from 'node:assert';
+import { test } from 'node:test';
+
+test('synchronous passing test', () => {
+    assert.strictEqual(1, 1);
+});

Diff for: packages/node-test-floating-promises/package.json

@@ -0,0 +1,23 @@
+{
+  "name": "node-test-floating-promises",
+  "version": "0.0.0",
+  "description": "Example of using `node:test` with `@typescript-eslint/no-floating-promises`'s `allowForKnownSafeCalls` option.",
+  "main": "index.ts",
+  "repository": {
+    "directory": "packages/node-test-floating-promises",
+    "type": "git",
+    "url": "https://github.com/typescript-eslint/typescript-eslint-examples"
+  },
+  "license": "MIT",
+  "devDependencies": {
+    "@types/node": "^22.10.7",
+    "eslint": "^9.16.0",
+    "typescript": "^5.7.2",
+    "typescript-eslint": "^8.18.0"
+  },
+  "scripts": {
+    "lint": "eslint .",
+    "tsc": "tsc"
+  },
+  "type": "module"
+}

Diff for: packages/node-test-floating-promises/tsconfig.json

@@ -0,0 +1,8 @@
+{
+  "compilerOptions": {
+    "module": "NodeNext",
+    "moduleResolution": "NodeNext",
+    "noEmit": true,
+    "strict": true
+  },
+}