Added rootNodes() method

Author: mtils

src/Ems/Contracts/Tree/NodeProvider.php

@@ -112,4 +112,11 @@ public function parent(CanHaveParent $child);
      * @return Node[]
      */
     public function ancestors(CanHaveParent $child);
+
+    /**
+     * Return all known root nodes.
+     *
+     * @return Node[]
+     */
+    public function rootNodes();
 }

src/Ems/Tree/Eloquent/NodeRepository.php

@@ -308,6 +308,25 @@ public function ancestors(CanHaveParent $child)
 
     }
 
+    /**
+     * {@inheritdoc}
+     *
+     * @return Node[]
+     */
+    public function rootNodes()
+    {
+        $query = $this->model->newQuery()->whereNull($this->parentIdKey);
+
+        $this->callBeforeListeners('rootNodes', [$query]);
+
+        $nodes = $query->get()->all();
+
+        $this->callAfterListeners('rootNodes', [$nodes]);
+
+        return $nodes;
+    }
+
+
     /**
      * @inheritDoc
      */

tests/integration/Tree/Eloquent/EloquentNodeRepositoryIntegrationTest.php

@@ -296,6 +296,37 @@ public function parent_returns_null_on_no_parent()
 
     }
 
+    /**
+     * @test
+     */
+    public function rootNodes_returns_one_rootNode()
+    {
+        $repo = $this->newRepository();
+
+        $rootNodes = $repo->rootNodes();
+
+        $this->assertCount(1, $rootNodes);
+
+    }
+
+    /**
+     * @test
+     */
+    public function rootNodes_returns_many_rootNodes()
+    {
+        $repo = $this->newRepository();
+
+        $rootNode2 = $repo->store(['name' => 'root-2']);
+
+        $rootNodes = $repo->rootNodes();
+
+        $this->assertCount(2, $rootNodes);
+
+        $this->assertEquals('root-1', $rootNodes[0]->getPathSegment());
+        $this->assertEquals('root-2', $rootNodes[1]->getPathSegment());
+
+    }
+
     /**
      * @test
      */