wip: code formatting nits continued

test/filter.spec.js

@@ -0,0 +1,10 @@
+import { isEven } from './utils';
+import filter from '../src/filter';
+
+describe('filter', () => {
+    const array = [1, 2, 3];
+
+    it('should return elements `predicate` returns truthy for', () => {
+        expect(filter(array, isEven)).toEqual([2]);
+    });
+});