Add tests and docs for tsup (bundler)

docs/bundler.md

@@ -9,6 +9,7 @@ A bundler plugin and specific instructions are available for the following bundl
 
 - [esbuild](./bundlers/esbuild.md)
 - [rolldown](./bundlers/rolldown.md)
+- [tsup](./bundlers/tsup.md)
 
 If your bundler is not listed here, please refer to the general guidelines below and consider reaching out to us for assistance.
 

docs/bundlers/tsup.md

@@ -0,0 +1,37 @@
+# Installing Zen in a Node.js Application Bundled with tsup
+
+Note: Zen runs only on the server side, it does not run in the browser.
+
+Note: If `bundle` is set to `false` in the tsup configuration, Zen will work without any additional configuration.
+For some general information about using Zen with bundlers, please refer to the [general bundler documentation](./bundler.md).
+
+## Using the Zen esbuild Plugin
+
+To use Zen with tsup, you need to install the `@aikidosec/firewall` package and add the Zen esbuild plugin to your bundler configuration like in the example below.
+
+```js
+import { cp, mkdir, writeFile } from "node:fs/promises";
+import { defineConfig } from "tsup";
+import { zenEsbuildPlugin } from "@aikidosec/firewall/bundler";
+
+export default defineConfig({
+  entry: ["src/app.ts"],
+  bundle: true,
+  platform: "node",
+  format: "cjs", // or "esm"
+  outDir: "dist",
+  esbuildPlugins: [zenEsbuildPlugin()], // <-- Add the Zen esbuild plugin here
+});
+```
+
+If you are using `cjs` as output format, add the following at the top of your application entry point, above any other imports, including Zen imports:
+
+```js
+require("@aikidosec/firewall/instrument");
+```
+
+Setting an explicit output directory and build format is mandatory for the plugin to work correctly.
+After configuring tsup with the Zen plugin, you can build your application like done before.
+However, **you need to ensure that the full output directory is deployed to your production environment.**
+
+If your output format is set to `esm`, please also follow the instructions in the [ESM documentation](../esm.md) and modify your start command accordingly.