Set default value of 'max_depth' in get_comment_reply_link().

Introduced in [8878].

Props d4z_c0nf.
Fixes #38170.

git-svn-id: https://develop.svn.wordpress.org/trunk@38669 602fd350-edb4-49c9-b593-d223f7449a82

tests/phpunit/tests/comment/getCommentReplyLink.php

@@ -0,0 +1,29 @@
+<?php
+
+/**
+ * @group comment
+ */
+class Tests_Comment_GetCommentReplyLink extends WP_UnitTestCase {
+	/**
+	 * @ticket 38170
+	 */
+	public function test_should_return_null_when_max_depth_is_less_than_depth() {
+		$args = array(
+			'depth' => 5,
+			'max_depth' => 4,
+		);
+
+		$this->assertNull( get_comment_reply_link( $args ) );
+	}
+
+	/**
+	 * @ticket 38170
+	 */
+	public function test_should_return_null_when_default_max_depth_is_less_than_depth() {
+		$args = array(
+			'depth' => 5,
+		);
+
+		$this->assertNull( get_comment_reply_link( $args ) );
+	}
+}