Rewrite esbuild postcss plugin

Signed-off-by: gearnode <bryan@frimin.fr>

packages/esbuild-plugin-postcss/tests/esbuild.test.mjs

@@ -0,0 +1,67 @@
+import { strict as assert } from "node:assert";
+import path from "node:path";
+import fs from "node:fs/promises";
+import os from "node:os";
+import * as esbuild from "esbuild";
+import postcssPlugin from "../src/index.mjs";
+import postcss from "postcss";
+import autoprefixer from "autoprefixer";
+
+// Create a temporary directory for our test
+const tmpDir = await fs.mkdtemp(
+  path.join(os.tmpdir(), "esbuild-postcss-test-"),
+);
+const inputFile = path.join(tmpDir, "input.css");
+const outputFile = path.join(tmpDir, "output.js");
+
+// Create a simple CSS file for testing
+const cssContent = `
+.example {
+  display: flex;
+  user-select: none;
+}
+`;
+
+// Write the test CSS file
+await fs.writeFile(inputFile, cssContent);
+
+// Test the plugin with autoprefixer
+try {
+  console.log("Testing PostCSS plugin with autoprefixer...");
+
+  const result = await esbuild.build({
+    entryPoints: [inputFile],
+    bundle: true,
+    outfile: outputFile,
+    plugins: [
+      postcssPlugin({
+        plugins: [autoprefixer],
+      }),
+    ],
+  });
+
+  console.log("Build completed successfully");
+
+  const outputContent = await fs.readFile(outputFile, "utf8");
+
+  assert(
+    outputContent.includes("-webkit-user-select"),
+    "Expected -webkit-user-select to be added by autoprefixer",
+  );
+  assert(
+    outputContent.includes("-moz-user-select"),
+    "Expected -moz-user-select to be added by autoprefixer",
+  );
+
+  console.log("Test passed: Autoprefixer correctly processed CSS");
+} catch (error) {
+  console.error("Test failed:", error);
+  process.exit(1);
+} finally {
+  try {
+    await fs.rm(tmpDir, { recursive: true, force: true });
+    console.log("Cleaned up temporary test files");
+  } catch (cleanupError) {
+    console.warn("Warning: Failed to clean up temporary files:", cleanupError);
+  }
+}