feat: enhance service providers with provides method and integrate command bus in handlers

tests/ServiceProviders/AbstractServiceProvider.php

@@ -28,16 +28,16 @@ abstract class AbstractServiceProvider extends Unit
         $this->assertInstanceOf($providerClass, $provider);
         $provider->register();
 
-        $bindings = $provider->bindings;
-        foreach ($bindings as $abstract => $concrete) {
-            $this->assertTrue($container->bound($abstract), "The $abstract is not bound in the container.");
-            $this->assertNotNull($container->make($abstract), "The $abstract could not be resolved.");
+        $abstract = $provider->provides()[0];
+        $concrete = get_class($container->make($abstract));
 
-            $this->assertInstanceOf(
-                $concrete,
-                $container->make($abstract),
-                "The $abstract is not an instance of $concrete."
-            );
-        }
+        $this->assertTrue($container->bound($abstract), "The $abstract is not bound in the container.");
+        $this->assertNotNull($container->make($abstract), "The $abstract could not be resolved.");
+
+        $this->assertInstanceOf(
+            $concrete,
+            $container->make($abstract),
+            "The $abstract is not an instance of $concrete."
+        );
     }
 }