add tests

tests/Pest.php

@@ -1,5 +1,6 @@
 <?php declare(strict_types=1);
 
+use Mockery\MockInterface;
 use Tests\TestCase;
 
 /*
@@ -24,7 +25,12 @@ uses(TestCase::class)->in('Feature', 'Unit');
 | global functions to help you to reduce the number of lines of code in your test files.
 |
 */
-function something(): void
+/**
+ * @template T of object
+ * @param class-string<T> $className
+ * @return MockInterface&T
+ */
+function createMock(string $className): MockInterface
 {
-    // ..
+    return Mockery::mock($className);
 }