Implement enhancement #43 with tests

src/SaveRelationsBehavior.php

@@ -766,7 +766,7 @@ class SaveRelationsBehavior extends Behavior
 
     /**
      * Return the old relations values.
-     * @return array
+     * @return array The old relations (name-value pairs)
      */
     public function getOldRelations()
     {
@@ -779,11 +779,40 @@ class SaveRelationsBehavior extends Behavior
 
     /**
      * Returns the old value of the named relation.
-     * @param $relationName
+     * @param $relationName The relations name as defined in the behavior `relations` parameter
      * @return mixed
      */
     public function getOldRelation($relationName)
     {
         return array_key_exists($relationName, $this->_oldRelationValue) ? $this->_oldRelationValue[$relationName] : $this->owner->{$relationName};
     }
+
+    /**
+     * Returns the relations that have been modified since they are loaded.
+     * @return array The changed relations (name-value pairs)
+     */
+    public function getDirtyRelations()
+    {
+        $dirtyRelations = [];
+        foreach ($this->_relations as $relationName) {
+            if (array_key_exists($relationName, $this->_oldRelationValue)) {
+                $dirtyRelations[$relationName] = $this->owner->{$relationName};
+            }
+        }
+        return $dirtyRelations;
+    }
+
+    /**
+     * Mark a relation as dirty
+     * @param $relationName
+     * @return bool Whether the operation succeeded.
+     */
+    public function markRelationDirty($relationName)
+    {
+        if (in_array($relationName, $this->_relations) && !array_key_exists($relationName, $this->_oldRelationValue)) {
+            $this->_oldRelationValue[$relationName] = $this->owner->{$relationName};
+            return true;
+        }
+        return false;
+    }
 }

tests/SaveRelationsBehaviorTest.php

@@ -950,4 +950,31 @@ class SaveRelationsBehaviorTest extends \PHPUnit_Framework_TestCase
         $this->assertEquals($oldCompany->name, 'Microsoft');
 
     }
+
+    public function testGetDirtyRelations()
+    {
+        $project = Project::findOne(1);
+        $project->company = Company::findOne(2);
+        $links = [
+            ['language' => 'fr', 'name' => 'windows10', 'link' => 'https://www.microsoft.com/fr-fr/windows/features', 'link_type_id' => 2],
+            ['language' => 'en', 'name' => 'windows10', 'link' => 'https://www.microsoft.com/en-us/windows/features', 'link_type_id' => 2]
+        ];
+        $project->links = $links;
+        $dirtyRelations = $project->getDirtyRelations();
+        $this->assertCount(2, $dirtyRelations);
+        $this->assertArrayHasKey('company', $dirtyRelations);
+        $this->assertArrayHasKey('links', $dirtyRelations);
+        $this->assertArrayNotHasKey('tags', $dirtyRelations);
+        $this->assertEquals($dirtyRelations['company'], $project->company);
+        $this->assertEquals($dirtyRelations['links'], $project->links);
+    }
+
+    public function testMarkRelationDirty()
+    {
+        $project = Project::findOne(1);
+        $this->assertArrayNotHasKey('company', $project->getDirtyRelations());
+        $this->assertFalse($project->markRelationDirty('wrongRelationName'));
+        $this->assertTrue($project->markRelationDirty('company'));
+        $this->assertArrayHasKey('company', $project->getDirtyRelations());
+    }
 }