Modify Model become abstract, create database interactions and do test.

_tests/unit/PostTest.php

@@ -0,0 +1,31 @@
+<?php
+namespace App\Models;
+
+class PostTest extends \PHPUnit\Framework\TestCase
+{
+    /**
+     *
+     * @test
+     */
+    public function showDataSuccess()
+    {
+        $post = new Post();
+
+        $this->assertTrue($post->showAll());
+
+        $fields = ['category', 'expired_at', 'creator', 'content'];
+        $values = ['3', '2017-09-02', '2', 'barbarbarbarbarbarbar!'];
+
+        $this->assertTrue($post->entry($fields, $values));
+
+        $args = ['category' => 5, 'content' => 'foofoofoofoo!'];
+
+        $this->assertTrue($post->update($args, 1));
+
+        $this->assertTrue($post->showSingle(1));
+
+        $this->assertTrue($post->delete(1));
+
+        $this->assertTrue($post->dropTable('pengumuman'));
+    }
+}