add tests

Author: Xstoudi

test/parallel/test-process-loadedmodules.js

@@ -3,5 +3,19 @@
 require('../common');
 const assert = require('assert');
 
+
+for (const mod of process.loadedModules) {
+  assert.strictEqual(typeof mod, 'string');
+}
+
+assert.strictEqual(
+  new Set(process.loadedModules).size,
+  process.loadedModules.length
+);
+
+assert.ok(!process.loadedModules.includes('cluster'))
+require('cluster');
+assert.ok(process.loadedModules.includes('cluster'))
+
 assert.ok(Array.isArray(process.loadedModules));
 assert.throws(() => process.loadedModules = 'foo', /^TypeError: Cannot set property loadedModules of #<process> which has only a getter$/);