Some small imrpovements in the dependency injection framework:

- camelCase methods changed to snake_case for consistency with WP.
- Added a check in `ExtendedContainer::get` that throws an informative
  exception if a non-namespaced class name is passed.
- `container->reset_resolved()` is called during unit testing bootstrap.
- Added some utility methods in `WC_Unit_Test_Case`.

src/DependencyManagement/AbstractServiceProvider.php

@@ -17,8 +17,8 @@ use League\Container\Definition\Definition;
  * See the documentation of the original class this one is based on (https://container.thephpleague.com/3.x/service-providers)
  * for basic usage details. What this class adds is:
  *
- * - The `addWithAutoArguments` method that allows to register classes without having to specify the constructor arguments.
- * - The `shareWithAutoArguments` method, sibling of the above.
+ * - The `add_with_auto_arguments` method that allows to register classes without having to specify the constructor arguments.
+ * - The `share_with_auto_arguments` method, sibling of the above.
  * - Convenience `add` and `share` methods that are just proxies for the same methods in `$this->getContainer()`.
  *
  * @package Automattic\WooCommerce\Tools\DependencyManagement
@@ -38,7 +38,7 @@ abstract class AbstractServiceProvider extends \League\Container\ServiceProvider
 	 *
 	 * @throws \Exception Error when reflecting the class, or class constructor is not public, or an argument has no valid type hint.
 	 */
-	public function addWithAutoArguments( string $class_name, $concrete = null, bool $shared = false ) : DefinitionInterface {
+	public function add_with_auto_arguments( string $class_name, $concrete = null, bool $shared = false ) : DefinitionInterface {
 		try {
 			$reflector = new \ReflectionClass( $class_name );
 		} catch ( \ReflectionException $ex ) {
@@ -90,8 +90,8 @@ abstract class AbstractServiceProvider extends \League\Container\ServiceProvider
 	 *
 	 * @throws \Exception Error when reflecting the class, or class constructor is not public, or an argument has no valid type hint.
 	 */
-	public function shareWithAutoArguments( string $class_name, $concrete = null ) : DefinitionInterface {
-		return $this->addWithAutoArguments( $class_name, $concrete, true );
+	public function share_with_auto_arguments( string $class_name, $concrete = null ) : DefinitionInterface {
+		return $this->add_with_auto_arguments( $class_name, $concrete, true );
 	}
 
 	/**

src/DependencyManagement/ExtendedContainer.php

@@ -37,7 +37,7 @@ class ExtendedContainer extends \League\Container\Container {
 	 * @throws \Exception Invalid parameters.
 	 */
 	public function add( string $id, $concrete = null, bool $shared = null ) : DefinitionInterface {
-		if ( ! $this->class_is_in_root_namespace( $id ) && ! in_array( $id, $this->registration_whitelist ) ) {
+		if ( ! $this->class_is_in_root_namespace( $id ) && ! in_array( $id, $this->registration_whitelist, true ) ) {
 			throw new \Exception( "Can't use the container to register '$id', only objects in the " . Container::WOOCOMMERCE_ROOT_NAMESPACE . ' namespace are allowed for registration.' );
 		}
 
@@ -82,4 +82,21 @@ class ExtendedContainer extends \League\Container\Container {
 			$definition->setConcrete( $concrete );
 		}
 	}
+
+	/**
+	 * Get an instance of a registered class.
+	 *
+	 * @param string $id The class name.
+	 * @param bool   $new True to generate a new instance even if the class was registered as shared.
+	 *
+	 * @return object An instance of the requested class.
+	 * @throws \Exception Attempt to get an instance of a non-namespaced class.
+	 */
+	public function get( $id, bool $new = false ) {
+		if ( false === strpos( $id, '\\' ) ) {
+			throw new \Exception( "Attempt to get an instance of the non-namespaced class '$id' from the container, did you forget to add a namespace import?" );
+		}
+
+		return parent::get( $id, $new );
+	}
 }

src/DependencyManagement/ServiceProviders/ProxiesServiceProvider.php

@@ -31,6 +31,6 @@ class ProxiesServiceProvider extends AbstractServiceProvider {
 	 */
 	public function register() {
 		$this->share( ActionsProxy::class );
-		$this->shareWithAutoArguments( LegacyProxy::class );
+		$this->share_with_auto_arguments( LegacyProxy::class );
 	}
 }

src/Proxies/ActionsProxy.php

@@ -25,7 +25,7 @@ class ActionsProxy {
 	 *
 	 * @return int The number of times action hook $tag is fired.
 	 */
-	public function didAction( $tag ) {
+	public function did_action( $tag ) {
 		return did_action( $tag );
 	}
 
@@ -38,7 +38,7 @@ class ActionsProxy {
 	 *
 	 * @return mixed The filtered value after all hooked functions are applied to it.
 	 */
-	public function applyFilters( $tag, $value, ...$parameters ) {
+	public function apply_filters( $tag, $value, ...$parameters ) {
 		return apply_filters( $tag, $value, ...$parameters );
 	}
 

src/Proxies/LegacyProxy.php

@@ -22,22 +22,6 @@ use \Psr\Container\ContainerInterface as Container;
  */
 class LegacyProxy {
 
-	/**
-	 * Holds the instance of the container to use.
-	 *
-	 * @var Container
-	 */
-	private $container;
-
-	/**
-	 * Creates a new instance of the class.
-	 *
-	 * @param Container $container The container to use.
-	 */
-	public function __construct( Container $container ) {
-		$this->container = $container;
-	}
-
 	/**
 	 * Gets an instance of a given legacy class.
 	 * This must not be used to get instances of classes in the `src` directory.
@@ -47,14 +31,14 @@ class LegacyProxy {
 	 * @return object The instance of the class.
 	 * @throws \Exception The requested class belongs to the `src` directory, or there was an error creating an instance of the class.
 	 */
-	public function getInstanceOf( string $class_name ) {
-		if ( $this->container->has( $class_name ) ) {
+	public function get_instance_of( string $class_name ) {
+		if ( false !== strpos( $class_name, '\\' ) ) {
 			throw new \Exception( 'The LegacyProxy class is not intended for getting instances of classes in the src directory, please use constructor injection or the instance of \\Psr\\Container\\ContainerInterface for that.' );
 		}
 
 		try {
 			// If a class has a special procedure to obtain a instance, use it.
-			$instance = $this->getSpecialInstanceOf( $class_name );
+			$instance = $this->get_special_instance_of( $class_name );
 			if ( ! is_null( $instance ) ) {
 				return $instance;
 			}
@@ -78,7 +62,7 @@ class LegacyProxy {
 	 *
 	 * @return object|null The instance, or null if there's no special procedure for that class.
 	 */
-	private function getSpecialInstanceOf( string $class_name ) {
+	private function get_special_instance_of( string $class_name ) {
 		if ( \WC_Queue_Interface::class === $class_name ) {
 			return \WC_Queue::instance();
 		}
@@ -95,7 +79,7 @@ class LegacyProxy {
 	 *
 	 * @return mixed The result from the function.
 	 */
-	public function callFunction( $function_name, ...$parameters ) {
+	public function call_function( $function_name, ...$parameters ) {
 		return call_user_func_array( $function_name, $parameters );
 	}
 
@@ -109,7 +93,7 @@ class LegacyProxy {
 	 *
 	 * @return mixed The result from the method.
 	 */
-	public function callStatic( $class_name, $method_name, ...$parameters ) {
+	public function call_static( $class_name, $method_name, ...$parameters ) {
 		return call_user_func_array( "$class_name::$method_name", $parameters );
 	}
 }

tests/Tools/DependencyManagement/MockableLegacyProxy.php

@@ -118,12 +118,12 @@ class MockableLegacyProxy extends \Automattic\WooCommerce\Proxies\LegacyProxy {
 	 *
 	 * @return mixed The result from the function or mock callback.
 	 */
-	public function callFunction( $function_name, ...$parameters ) {
+	public function call_function( $function_name, ...$parameters ) {
 		if ( array_key_exists( $function_name, $this->mocked_functions ) ) {
 			return call_user_func_array( $this->mocked_functions[ $function_name ], $parameters );
 		}
 
-		return parent::callFunction( $function_name, ...$parameters );
+		return parent::call_function( $function_name, ...$parameters );
 	}
 
 	/**
@@ -139,7 +139,7 @@ class MockableLegacyProxy extends \Automattic\WooCommerce\Proxies\LegacyProxy {
 	 *
 	 * @return mixed The result from the method or mock callback.
 	 */
-	public function callStatic( $class_name, $method_name, ...$parameters ) {
+	public function call_static( $class_name, $method_name, ...$parameters ) {
 		if ( array_key_exists( $class_name, $this->mocked_statics ) ) {
 			$class_mocks = $this->mocked_statics[ $class_name ];
 			if ( array_key_exists( $method_name, $class_mocks ) ) {
@@ -148,7 +148,7 @@ class MockableLegacyProxy extends \Automattic\WooCommerce\Proxies\LegacyProxy {
 			}
 		}
 
-		return parent::callStatic( $class_name, $method_name, ...$parameters );
+		return parent::call_static( $class_name, $method_name, ...$parameters );
 	}
 
 	/**
@@ -163,12 +163,12 @@ class MockableLegacyProxy extends \Automattic\WooCommerce\Proxies\LegacyProxy {
 	 * @return object The (possibly mocked) instance of the class.
 	 * @throws \Exception The requested class belongs to the `src` directory, or there was an error creating an instance of the class.
 	 */
-	public function getInstanceOf( string $class_name ) {
+	public function get_instance_of( string $class_name ) {
 		if ( array_key_exists( $class_name, $this->mocked_classes ) ) {
 			$mock = $this->mocked_classes[ $class_name ];
 			return is_callable( $mock ) ? call_user_func( $mock, $class_name ) : $mock;
 		}
 
-		return parent::getInstanceOf( $class_name );
+		return parent::get_instance_of( $class_name );
 	}
 }

tests/legacy/bootstrap.php

@@ -11,7 +11,6 @@ use Automattic\WooCommerce\Testing\Tools\CodeHacking\CodeHacker;
 use Automattic\WooCommerce\Testing\Tools\CodeHacking\Hacks\StaticMockerHack;
 use Automattic\WooCommerce\Testing\Tools\CodeHacking\Hacks\FunctionsMockerHack;
 use Automattic\WooCommerce\Testing\Tools\CodeHacking\Hacks\BypassFinalsHack;
-
 use Automattic\WooCommerce\Testing\Tools\DependencyManagement\MockableLegacyProxy;
 
 /**
@@ -127,6 +126,7 @@ class WC_Unit_Tests_Bootstrap {
 		$inner_container = $inner_container_property->getValue( wc_get_container() );
 
 		$inner_container->replace( LegacyProxy::class, MockableLegacyProxy::class );
+		$inner_container->reset_resolved();
 
 		$GLOBALS['wc_container'] = $inner_container;
 	}

tests/legacy/framework/class-wc-unit-test-case.php

@@ -152,6 +152,31 @@ class WC_Unit_Test_Case extends WP_HTTP_TestCase {
 		return $result;
 	}
 
+	/**
+	 * Get an instance of a class that has been registered in the dependency injection container.
+	 * To get an instance of a legacy class (such as the ones in the 'íncludes' directory) use
+	 * 'get_legacy_instance_of' instead.
+	 *
+	 * @param string $class_name The class name to get an instance of.
+	 *
+	 * @return mixed The instance.
+	 */
+	public function get_instance_of( string $class_name ) {
+		return wc_get_container()->get( $class_name );
+	}
+
+	/**
+	 * Get an instance of  legacy class (such as the ones in the 'íncludes' directory).
+	 * To get an instance of a class registered in the dependency injection container use 'get_instance_of' instead.
+	 *
+	 * @param string $class_name The class name to get an instance of.
+	 *
+	 * @return mixed The instance.
+	 */
+	public function get_legacy_instance_of( string $class_name ) {
+		return wc_get_container()->get( LegacyProxy::class )->get_instance_of( $class_name );
+	}
+
 	/**
 	 * Reset all the cached resolutions in the dependency injection container, so any further "get"
 	 * for shared definitions will generate the instance again.
@@ -161,6 +186,13 @@ class WC_Unit_Test_Case extends WP_HTTP_TestCase {
 		wc_get_container()->reset_resolved();
 	}
 
+	/**
+	 * Reset the mock legacy proxy class so that all the registered mocks are unregistered.
+	 */
+	public function reset_legacy_proxy_mocks() {
+		wc_get_container()->get( LegacyProxy::class )->reset();
+	}
+
 	/**
 	 * Register the function mocks to use in the mockable LegacyProxy.
 	 *