test: improve UV_THREADPOOL_SIZE tests on .env

PR-URL: #49213
Reviewed-By: Chemi Atlow <chemi@atlow.co.il>
Reviewed-By: Geoffrey Booth <webadmin@geoffreybooth.com>

test/fixtures/dotenv/uv-threadpool.env

@@ -0,0 +1 @@
+UV_THREADPOOL_SIZE=4

test/node-api/test_uv_threadpool_size/node-options.js

@@ -0,0 +1,31 @@
+'use strict';
+
+const common = require('../../common');
+const assert = require('assert');
+const path = require('path');
+const { spawnSync } = require('child_process');
+
+if (process.config.variables.node_without_node_options) {
+  common.skip('missing NODE_OPTIONS support');
+}
+
+const uvThreadPoolPath = '../../fixtures/dotenv/uv-threadpool.env';
+
+// Should update UV_THREADPOOL_SIZE
+let filePath = path.join(__dirname, `./build/${common.buildType}/test_uv_threadpool_size`);
+if (common.isWindows) {
+  filePath = filePath.replaceAll('\\', '\\\\');
+}
+const code = `
+   const { test } = require('${filePath}');
+   const size = parseInt(process.env.UV_THREADPOOL_SIZE, 10);
+   require('assert').strictEqual(size, 4);
+   test(size);
+ `.trim();
+const child = spawnSync(
+  process.execPath,
+  [ `--env-file=${uvThreadPoolPath}`, '--eval', code ],
+  { cwd: __dirname, encoding: 'utf-8' },
+);
+assert.strictEqual(child.stderr, '');
+assert.strictEqual(child.status, 0);

test/parallel/test-dotenv-node-options.js

@@ -62,17 +62,4 @@ describe('.env supports NODE_OPTIONS', () => {
     assert.strictEqual(child.code, 0);
   });
 
-  it('should update UV_THREADPOOL_SIZE', async () => {
-    const code = `
-      require('assert').strictEqual(process.env.UV_THREADPOOL_SIZE, '5')
-    `.trim();
-    const child = await common.spawnPromisified(
-      process.execPath,
-      [ `--env-file=${relativePath}`, '--eval', code ],
-      { cwd: __dirname },
-    );
-    assert.strictEqual(child.stderr, '');
-    assert.strictEqual(child.code, 0);
-  });
-
 });