Ported Down changes from PR#10919

From db79dbf Mon Sep 17 00:00:00 2001
From: freakphp <mail@freak.io>
Date: Sun, 17 Sep 2017 12:52:00 +0200
Subject: [PATCH 1/2] magento#10803 update OrderService to return correct bool value for cancel method

From d4cddf7 Mon Sep 17 00:00:00 2001
From: Ievgen Shakhsuvarov <ishakhsuvarov@users.noreply.github.com>
Date: Mon, 18 Sep 2017 12:22:00 +0200
Subject: [PATCH 2/2] magento#10919: update OrderService to return correct bool value

app/code/Magento/Sales/Model/Service/OrderService.php

@@ -87,7 +87,8 @@ public function __construct(
     public function cancel($id)
     {
         $order = $this->orderRepository->get($id);
-        if ((bool)$order->cancel()) {
+        if ($order->canCancel()) {
+            $order->cancel();
             $this->orderRepository->save($order);
             return true;
         }

app/code/Magento/Sales/Test/Unit/Model/Service/OrderServiceTest.php

@@ -163,9 +163,30 @@ public function testCancel()
         $this->orderMock->expects($this->once())
             ->method('cancel')
             ->willReturn($this->orderMock);
+        $this->orderMock->expects($this->once())
+            ->method('canCancel')
+            ->willReturn(true);
         $this->assertTrue($this->orderService->cancel(123));
     }
 
+    /**
+     * test for Order::cancel() fail case
+     */
+    public function testCancelFailed()
+    {
+        $this->orderRepositoryMock->expects($this->once())
+            ->method('get')
+            ->with(123)
+            ->willReturn($this->orderMock);
+        $this->orderMock->expects($this->never())
+            ->method('cancel')
+            ->willReturn($this->orderMock);
+        $this->orderMock->expects($this->once())
+            ->method('canCancel')
+            ->willReturn(false);
+        $this->assertFalse($this->orderService->cancel(123));
+    }
+
     public function testGetCommentsList()
     {
         $this->filterBuilderMock->expects($this->once())