Add test for previous commit.

tests/TestCase/Database/Expression/ComparisonTest.php

@@ -0,0 +1,38 @@
+<?php
+/**
+ * CakePHP(tm) : Rapid Development Framework (https://cakephp.org)
+ * Copyright (c) Cake Software Foundation, Inc. (https://cakefoundation.org)
+ *
+ * Licensed under The MIT License
+ * For full copyright and license information, please see the LICENSE.txt
+ * Redistributions of files must retain the above copyright notice.
+ *
+ * @copyright     Copyright (c) Cake Software Foundation, Inc. (https://cakefoundation.org)
+ * @link          https://cakephp.org CakePHP(tm) Project
+ * @since         3.7.5
+ * @license       https://opensource.org/licenses/mit-license.php MIT License
+ */
+namespace Cake\Test\TestCase\Database\Expression;
+
+use Cake\Database\Expression\Comparison;
+use Cake\Database\Expression\QueryExpression;
+use Cake\TestSuite\TestCase;
+
+/**
+ * Tests Comparison class
+ */
+class ComparisonTest extends TestCase
+{
+    /**
+     * Tests that cloning Comparion instance clones it's value and field expressions.
+     *
+     * @return void
+     */
+    public function testClone()
+    {
+        $exp = new Comparison(new QueryExpression('field1'), 1, 'integer', '<');
+        $exp2 = clone $exp;
+
+        $this->assertNotSame($exp->getField(), $exp2->getField());
+    }
+}