Updated the test system

test/remove.test.js

@@ -0,0 +1,9 @@
+const expect = require('expect');
+const {remove} = require('./_30s.js');
+
+test('remove is a Function', () => {
+  expect(remove).toBeInstanceOf(Function);
+});
+test('Removes elements from an array for which the given function returns false', () => {
+  expect(remove([1, 2, 3, 4], n => n % 2 === 0)).toEqual([2, 4]);
+});