IHF: relative_path helper added with tests.

Author: dmitry-ivanov

src/filesystem.php

@@ -0,0 +1,10 @@
+<?php
+
+use Symfony\Component\Filesystem\Filesystem;
+
+if (!function_exists('relative_path')) {
+    function relative_path($to, $from)
+    {
+        return (new Filesystem)->makePathRelative(realpath($to), realpath($from));
+    }
+}

tests/HelperFunctions/filesystem/RelativePathTest.php

@@ -0,0 +1,44 @@
+<?php
+
+namespace Illuminated\Helpers\HelperFunctions\Tests\FileSystem;
+
+use Illuminated\Helpers\HelperFunctions\Tests\TestCase;
+
+class RelativePathTest extends TestCase
+{
+    /** @test */
+    public function it_returns_relative_path_for_two_folders()
+    {
+        $path1 = realpath(__DIR__ . '/../../../src/');
+        $path2 = realpath(__DIR__ . '/../../../tests/HelperFunctions/filesystem');
+
+        $this->assertEquals('../../../src/', relative_path($path1, $path2));
+    }
+
+    /** @test */
+    public function it_correctly_works_with_params_which_are_relative_paths()
+    {
+        $path1 = __DIR__ . '/../../../src/';
+        $path2 = __DIR__ . '/../../../tests/HelperFunctions/filesystem';
+
+        $this->assertEquals('../../../src/', relative_path($path1, $path2));
+    }
+
+    /** @test */
+    public function it_correctly_works_for_the_same_folder()
+    {
+        $path1 = __DIR__;
+        $path2 = __DIR__;
+
+        $this->assertEquals('./', relative_path($path1, $path2));
+    }
+
+    /** @test */
+    public function even_if_the_paths_are_relative_and_different()
+    {
+        $path1 = __DIR__;
+        $path2 = __DIR__ . '/../../../tests/HelperFunctions/filesystem';
+
+        $this->assertEquals('./', relative_path($path1, $path2));
+    }
+}