Fix the getting of the Serializer Json mock object to match the coding standards and add a space after each comman in the function call

Author: dmanners

app/code/Magento/Checkout/Test/Unit/Block/Cart/ShippingTest.php

@@ -74,7 +74,7 @@ protected function setUp()
 
         $this->storeManager = $this->getMock(\Magento\Store\Model\StoreManagerInterface::class);
         $this->context->expects($this->once())->method('getStoreManager')->willReturn($this->storeManager);
-        $this->serializer = $this->getMock(\Magento\Framework\Serialize\Serializer\Json::class,[],[],'',false);
+        $this->serializer = $this->getMock(\Magento\Framework\Serialize\Serializer\Json::class, [], [], '', false);
 
         $this->model = new \Magento\Checkout\Block\Cart\Shipping(
             $this->context,

app/code/Magento/Checkout/Test/Unit/Block/Cart/SidebarTest.php

@@ -99,7 +99,7 @@ protected function setUp()
             ->method('getRequest')
             ->will($this->returnValue($this->requestMock));
 
-        $this->serializer = $this->getMock(\Magento\Framework\Serialize\Serializer\Json::class,[],[],'',false);
+        $this->serializer = $this->getMock(\Magento\Framework\Serialize\Serializer\Json::class, [], [], '', false);
 
         $this->model = $this->_objectManager->getObject(
             \Magento\Checkout\Block\Cart\Sidebar::class,

app/code/Magento/Checkout/Test/Unit/Block/OnepageTest.php

@@ -59,7 +59,7 @@ protected function setUp()
             false
         );
 
-        $this->serializer = $this->getMock(\Magento\Framework\Serialize\Serializer\Json::class,[],[],'',false);
+        $this->serializer = $this->getMock(\Magento\Framework\Serialize\Serializer\Json::class, [], [], '', false);
 
         $this->model = new \Magento\Checkout\Block\Onepage(
             $contextMock,