refactor: sort-files -> common utils

utils/sort-files.test.js

@@ -0,0 +1,26 @@
+/* global expect */
+
+const { sortFiles } = require('./sort-files');
+const { challengeFiles } = require('./__fixtures__/challenges');
+
+describe('sort-files', () => {
+  describe('sortFiles', () => {
+    it('should return an array', () => {
+      const sorted = sortFiles(challengeFiles);
+      expect(Array.isArray(sorted)).toBe(true);
+    });
+    it('should not modify the challenges', () => {
+      const sorted = sortFiles(challengeFiles);
+      const expected = Object.values(challengeFiles);
+      expect(sorted).toEqual(expect.arrayContaining(expected));
+      expect(sorted.length).toEqual(expected.length);
+    });
+
+    it('should sort the objects into html, js, css order', () => {
+      const sorted = sortFiles(challengeFiles);
+      const sortedKeys = sorted.map(({ key }) => key);
+      const expected = ['indexhtml', 'indexjsx', 'indexjs', 'indexcss'];
+      expect(sortedKeys).toStrictEqual(expected);
+    });
+  });
+});