Fix test code to run with any number of contents

Author: raeperd

lib/article.test.ts

@@ -1,7 +1,7 @@
 import { findFirstArticleBySlug, getAllArticleSlugs, getArticlePreviews } from './article';
 
 test('getArticlePreviews', () => {
-  const pageSize = 3
+  const pageSize = 1
   const articles = getArticlePreviews(1, pageSize)
 
   expect(articles.pageSize).toBe(pageSize)
@@ -10,7 +10,7 @@ test('getArticlePreviews', () => {
 
 test('getAllArticleSlugs', () => {
   const articleSlugs = getAllArticleSlugs()
-  expect(articleSlugs).toHaveLength(5)
+  expect(articleSlugs.length).toBeGreaterThanOrEqual(1)
 })
 
 test('findFirstArticleBySlug', () => {