Add autoloader for tests, phpunit config

tests/bootstrap.php

@@ -0,0 +1,25 @@
+<?PHP
+declare(strict_types = 1);
+
+/**
+ * Autoloader for musdb.
+ *
+ * @param string $className Name of the class to load.
+ *
+ * @return void
+ */
+\spl_autoload_register(function(string $className):void {
+
+    // Try using class map as defined through /scripts/buildClassMap.php
+
+    foreach (array_merge([__DIR__ . '/../tests', __DIR__ . '/../src', __DIR__ . '/../src/enums', __DIR__ . '/../../MD_STD/src', __DIR__ . '/../../MDErrorReporter', __DIR__ . '/../../MDErrorReporter/exceptions', __DIR__ . '/../../MDErrorReporter/exceptions/generic', __DIR__ . '/../../MDErrorReporter/exceptions/updates']) as $classDir) {
+
+        if (\file_exists("$classDir/$className.php")) {
+            include "$classDir/$className.php";
+            return;
+        }
+
+    }
+
+});
+