Test coverage for every line!

src/functions.php

@@ -23,7 +23,7 @@ namespace Aviat\Ion;
  * @param string[] ...$args
  * @return string
  */
-function _dir(...$args)
+function _dir(string ...$args): string
 {
 	return implode(DIRECTORY_SEPARATOR, $args);
 }

tests/functionsTest.php

@@ -0,0 +1,33 @@
+<?php declare(strict_types=1);
+/**
+ * Ion
+ *
+ * Building blocks for web development
+ *
+ * PHP version 7
+ *
+ * @package     Ion
+ * @author      Timothy J. Warren <tim@timshomepage.net>
+ * @copyright   2015 - 2017 Timothy J. Warren
+ * @license     http://www.opensource.org/licenses/mit-license.html  MIT License
+ * @version     2.0.0
+ * @link        https://git.timshomepage.net/timw4mail/ion
+ */
+
+namespace Aviat\Ion\Tests;
+
+use function Aviat\Ion\_dir;
+
+use PHPUnit\Framework\TestCase;
+
+class functionsTest extends TestCase {
+
+
+	public function test_dir()
+	{
+		$args = ['foo', 'bar', 'baz'];
+		$expected = implode(\DIRECTORY_SEPARATOR, $args);
+
+		$this->assertEquals(_dir(...$args), $expected);
+	}
+}