Add new koan

koans/EmptyIsNullOrIssetKoan.php

@@ -0,0 +1,66 @@
+<?php
+
+namespace PhpKoans;
+use PHPUnit\Framework\TestCase;
+defined('__') or define('__', null);
+
+class EmptyIsNullOrIssetKoan extends TestCase
+{
+    /**
+     * @test
+     */
+    function testMethodIsNull()
+    {
+        //is_null return true if variable is null
+        $this->assertEquals(__, is_null(NULL));
+        $this->assertEquals(__, is_null(""));
+    }
+
+    /**
+     * @test
+     */
+    function testMethodIsset()
+    {
+        //isset return true if variable exist and it is not null
+        $this->assertEquals(__, isset($something));
+
+        $array = array('bar' => 1, 'foo' => null);
+        $this->assertEquals(__, isset($array));
+        $this->assertEquals(__ , isset($array['bar']));
+        $this->assertEquals(__ , isset($array['foo']));
+        $this->assertEquals(__ , isset($array['barfoo']));
+
+    }
+
+    /**
+     * @test
+     */
+    function testMethodEmpty()
+    {
+        //Working with numbers. Returns true if is 0
+        $this->assertEquals(__, empty(0));
+        $this->assertEquals(__, empty(1));
+
+        //Working with decimals. Returns true if is 0.0
+        $this->assertEquals(__, empty(0.0));
+        $this->assertEquals(__, empty(0.1));
+
+        //Working wiht strings. Return false if has any character.
+        $this->assertEquals(__, empty(""));
+        $this->assertEquals(__, empty(" "));
+
+        //Working with booleans. Return false if is true
+        $this->assertEquals(__, empty(false));
+        $this->assertEquals(__, empty(true));
+
+        //working with arrays. Return true if the array has any value.
+        $this->assertEquals(__, empty(array()));
+        $this->assertEquals(__, empty(array(1)));
+
+        //working with objects. Return true if value is an instance
+        $this->assertEquals(__, empty((object)array()));
+        $this->assertEquals(__, empty(null));
+        $this->assertEquals(__, empty($something));
+    }
+}
+?>