Update Filter\ImportMetaFilter

Apply the filter to each record if it is a multi-record meta #56

inc/Import/Filter/ImportMetaFilter.php

@@ -45,13 +45,34 @@ public function __construct(
 	 */
 	public function filter_value( Type\ImportMetaInterface $meta, $object_id ) {
 
+		if ( $meta->is_single() )
+			return $this->apply_filters( $meta, $meta->value(), $object_id );
+
+		$value = [];
+		foreach ( $meta->value() as $v ) {
+			$value[] = $this->apply_filters( $meta, $v, $object_id );
+		}
+
+		return $value;
+	}
+
+	/**
+	 * @param Type\ImportMetaInterface $meta
+	 * @param string $value
+	 * @param int $object_id
+	 *
+	 * @return mixed
+	 */
+	public function apply_filters( Type\ImportMetaInterface $meta, $value, $object_id ) {
+
 		$filters = $this->filter_list->get_filters( $this->type, $meta->key() );
-		$value   = $meta->value();
 		foreach ( $filters as $filter ) {
 			if ( ! $filter->is_filterable( $meta->value(), $object_id ) ) {
 				/**
 				 * Fires when a filter is invalid (due to missing data)
 				 *
+				 * Todo: Check if these parameter are sufficient for multiple meta records!
+				 *
 				 * @param string $type ('post', 'comment', 'user' or 'term')
 				 * @param int $object_id
 				 * @param Type\ImportMetaInterface $meta

inc/Import/Filter/ImportMetaFilterInterface.php

@@ -18,7 +18,7 @@ interface ImportMetaFilterInterface {
 	 * @param Type\ImportMetaInterface $meta
 	 * @param int $object_id
 	 *
-	 * @return mixed (The filtered value)
+	 * @return mixed (The filtered value. This MUST be an array if $meta->is_single() is false!)
 	 */
 	public function filter_value( Type\ImportMetaInterface $meta, $object_id );
 }

tests/phpunit/Unit/Import/Filter/ImportMetaFilterTest.php

@@ -13,4 +13,10 @@ public function test_filter_value() {
 		// Todo: Write tests for
 		$this->markTestIncomplete( 'Under construction' );
 	}
+
+	public function test_apply_filters() {
+
+		// Todo: Write tests for
+		$this->markTestIncomplete( 'Under construction' );
+	}
 }