diff --git a/dev/tests/functional/tests/app/Magento/Cms/Test/TestCase/GridFilteringTest.xml b/dev/tests/functional/tests/app/Magento/Cms/Test/TestCase/GridFilteringTest.xml
index 715190039162b4fdbab91af72ca564e0c0732858..0b237e506636cf1beb8ff22122c515079cda176e 100644
--- a/dev/tests/functional/tests/app/Magento/Cms/Test/TestCase/GridFilteringTest.xml
+++ b/dev/tests/functional/tests/app/Magento/Cms/Test/TestCase/GridFilteringTest.xml
@@ -8,7 +8,7 @@
 <config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../../../../../../vendor/magento/mtf/etc/variations.xsd">
     <testCase name="Magento\Ui\Test\TestCase\GridFilteringTest" summary="Grid UI Component Filtering" ticketId="MAGETWO-41329">
         <variation name="CmsPageGridFiltering">
-            <data name="tag" xsi:type="string">severity:S2</data>
+            <data name="tag" xsi:type="string">severity:S3</data>
             <data name="description" xsi:type="string">Verify cms page grid filtering</data>
             <data name="itemsCount" xsi:type="string">2</data>
             <data name="fixtureName" xsi:type="string">cmsPage</data>
@@ -29,7 +29,7 @@
             <constraint name="\Magento\Ui\Test\Constraint\AssertGridFiltering"/>
         </variation>
         <variation name="CmsBlockGridFiltering">
-            <data name="tag" xsi:type="string">severity:S2</data>
+            <data name="tag" xsi:type="string">severity:S3</data>
             <data name="description" xsi:type="string">Verify cms block grid filtering</data>
             <data name="itemsCount" xsi:type="string">2</data>
             <data name="fixtureName" xsi:type="string">cmsBlock</data>
diff --git a/dev/tests/functional/tests/app/Magento/Cms/Test/TestCase/GridFullTextSearchTest.xml b/dev/tests/functional/tests/app/Magento/Cms/Test/TestCase/GridFullTextSearchTest.xml
index fc279aad59d3d7e21590be2c256f83831e7295cf..b17f32db04b23727a6583db5227dbf79d0f0d19d 100644
--- a/dev/tests/functional/tests/app/Magento/Cms/Test/TestCase/GridFullTextSearchTest.xml
+++ b/dev/tests/functional/tests/app/Magento/Cms/Test/TestCase/GridFullTextSearchTest.xml
@@ -8,7 +8,7 @@
 <config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../../../../../../vendor/magento/mtf/etc/variations.xsd">
     <testCase name="Magento\Ui\Test\TestCase\GridFullTextSearchTest" summary="Grid UI Component Full Text Search" ticketId="MAGETWO-41023">
         <variation name="CmsPageGridFullTextSearch">
-            <data name="tag" xsi:type="string">severity:S2, stable:no</data>
+            <data name="tag" xsi:type="string">severity:S3, stable:no</data>
             <data name="description" xsi:type="string">Verify cms page grid full text search</data>
             <data name="itemsCount" xsi:type="string">2</data>
             <data name="fixtureName" xsi:type="string">cmsPage</data>
@@ -20,7 +20,7 @@
             <constraint name="Magento\Ui\Test\Constraint\AssertGridFullTextSearch"/>
         </variation>
         <variation name="CmsBlockGridFullTextSearch">
-            <data name="tag" xsi:type="string">severity:S2</data>
+            <data name="tag" xsi:type="string">severity:S3</data>
             <data name="description" xsi:type="string">Verify cms blocks grid full text search</data>
             <data name="itemsCount" xsi:type="string">2</data>
             <data name="fixtureName" xsi:type="string">cmsBlock</data>
diff --git a/dev/tests/functional/tests/app/Magento/Cms/Test/TestCase/GridSortingTest.xml b/dev/tests/functional/tests/app/Magento/Cms/Test/TestCase/GridSortingTest.xml
index 1be7e61f6bd0ea27a99733a63828f438ab481215..053d32a0598ef1677cf67c83c307aa2352ac7803 100644
--- a/dev/tests/functional/tests/app/Magento/Cms/Test/TestCase/GridSortingTest.xml
+++ b/dev/tests/functional/tests/app/Magento/Cms/Test/TestCase/GridSortingTest.xml
@@ -8,7 +8,7 @@
 <config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../../../../../../vendor/magento/mtf/etc/variations.xsd">
     <testCase name="Magento\Ui\Test\TestCase\GridSortingTest" summary="Grid UI Component Sorting" ticketId="MAGETWO-41328">
         <variation name="CmsPagesGridSorting">
-            <data name="tag" xsi:type="string">severity:S2, stable:no</data>
+            <data name="tag" xsi:type="string">severity:S3, stable:no</data>
             <data name="description" xsi:type="string">Verify cms page grid sorting</data>
             <data name="columnsForSorting" xsi:type="array">
                 <item name="id" xsi:type="string">ID</item>
@@ -19,7 +19,7 @@
             <constraint name="Magento\Ui\Test\Constraint\AssertGridSorting"/>
         </variation>
         <variation name="CmsBlocksGridSorting">
-            <data name="tag" xsi:type="string">severity:S2, stable:no</data>
+            <data name="tag" xsi:type="string">severity:S3, stable:no</data>
             <data name="description" xsi:type="string">Verify cms blocks grid sorting</data>
             <data name="steps" xsi:type="array">
                 <item name="0" xsi:type="string">-</item>
diff --git a/dev/tests/functional/tests/app/Magento/Customer/Test/TestCase/GridFilteringTest.xml b/dev/tests/functional/tests/app/Magento/Customer/Test/TestCase/GridFilteringTest.xml
index 918f723981faac5a3a919caaf99ac9e75b0bf1bd..42a3103ce33d7615fcbfd06084bebfa965769b60 100644
--- a/dev/tests/functional/tests/app/Magento/Customer/Test/TestCase/GridFilteringTest.xml
+++ b/dev/tests/functional/tests/app/Magento/Customer/Test/TestCase/GridFilteringTest.xml
@@ -8,6 +8,7 @@
 <config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../../../../../../vendor/magento/mtf/etc/variations.xsd">
     <testCase name="Magento\Ui\Test\TestCase\GridFilteringTest" summary="Grid UI Component Filtering" ticketId="MAGETWO-41329">
         <variation name="CustomerGridFiltering">
+            <data name="tag" xsi:type="string">severity:S2</data>
             <data name="description" xsi:type="string">Verify customer page grid filtering</data>
             <data name="itemsCount" xsi:type="string">2</data>
             <data name="fixtureName" xsi:type="string">customer</data>
diff --git a/dev/tests/functional/tests/app/Magento/Customer/Test/TestCase/GridFullTextSearchTest.xml b/dev/tests/functional/tests/app/Magento/Customer/Test/TestCase/GridFullTextSearchTest.xml
index 00a2955be126a67b96d6ff8b03c706fe3b98d802..ef0bf7b7cea72e941840f103bb3700d66f06404c 100644
--- a/dev/tests/functional/tests/app/Magento/Customer/Test/TestCase/GridFullTextSearchTest.xml
+++ b/dev/tests/functional/tests/app/Magento/Customer/Test/TestCase/GridFullTextSearchTest.xml
@@ -8,6 +8,7 @@
 <config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../../../../../../vendor/magento/mtf/etc/variations.xsd">
     <testCase name="Magento\Ui\Test\TestCase\GridFullTextSearchTest" summary="Grid UI Component Full Text Search" ticketId="MAGETWO-41023">
         <variation name="CustomerGridFullTextSearch">
+            <data name="tag" xsi:type="string">severity:S2</data>
             <data name="description" xsi:type="string">Verify customer page grid full text search</data>
             <data name="itemsCount" xsi:type="string">2</data>
             <data name="fixtureName" xsi:type="string">customer</data>
diff --git a/dev/tests/functional/tests/app/Magento/Customer/Test/TestCase/GridSortingTest.xml b/dev/tests/functional/tests/app/Magento/Customer/Test/TestCase/GridSortingTest.xml
index b967fbd184526fd1d71fcf2055799842d0d018f1..7d6e7f6d8f1b4f3a2402e0ae1b659f60c941c63d 100644
--- a/dev/tests/functional/tests/app/Magento/Customer/Test/TestCase/GridSortingTest.xml
+++ b/dev/tests/functional/tests/app/Magento/Customer/Test/TestCase/GridSortingTest.xml
@@ -8,6 +8,7 @@
 <config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../../../../../../vendor/magento/mtf/etc/variations.xsd">
     <testCase name="Magento\Ui\Test\TestCase\GridSortingTest" summary="Grid UI Component Sorting" ticketId="MAGETWO-41328">
         <variation name="CustomerGridSorting">
+            <data name="tag" xsi:type="string">severity:S2</data>
             <data name="tag" xsi:type="string">stable:no</data>
             <data name="description" xsi:type="string">Verify customer page grid sorting</data>
             <data name="columnsForSorting" xsi:type="array">
diff --git a/dev/tests/functional/tests/app/Magento/Sales/Test/TestCase/GridFilteringTest.xml b/dev/tests/functional/tests/app/Magento/Sales/Test/TestCase/GridFilteringTest.xml
index b4c3a7568a2a1dd4fb62fe0d013b6425d372d27d..78c2676765418ebcbbae5ed21a8b0b0cb9ab1da8 100644
--- a/dev/tests/functional/tests/app/Magento/Sales/Test/TestCase/GridFilteringTest.xml
+++ b/dev/tests/functional/tests/app/Magento/Sales/Test/TestCase/GridFilteringTest.xml
@@ -8,6 +8,7 @@
 <config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../../../../../../vendor/magento/mtf/etc/variations.xsd">
     <testCase name="Magento\Ui\Test\TestCase\GridFilteringTest" summary="Grid UI Component Filtering" ticketId="MAGETWO-41328">
         <variation name="SalesOrderGridFiltering">
+            <data name="tag" xsi:type="string">severity:S2</data>
             <data name="tag" xsi:type="string">stable:no</data>
             <data name="description" xsi:type="string">Verify sales order grid filtering</data>
             <data name="steps" xsi:type="array">
@@ -33,6 +34,7 @@
             <constraint name="\Magento\Ui\Test\Constraint\AssertGridFiltering"/>
         </variation>
         <variation name="SalesInvoiceGridFiltering">
+            <data name="tag" xsi:type="string">severity:S3</data>
             <data name="description" xsi:type="string">Verify sales invoice grid filtering</data>
             <data name="steps" xsi:type="array">
                 <item name="0" xsi:type="string">Magento\Sales\Test\TestStep\CreateInvoiceStep</item>
@@ -56,6 +58,7 @@
             <constraint name="Magento\Ui\Test\Constraint\AssertGridFiltering"/>
         </variation>
         <variation name="SalesShipmentGridFiltering">
+            <data name="tag" xsi:type="string">severity:S3</data>
             <data name="description" xsi:type="string">Verify sales shipment grid filtering</data>
             <data name="steps" xsi:type="array">
                 <item name="0" xsi:type="string">Magento\Sales\Test\TestStep\CreateShipmentStep</item>
@@ -79,6 +82,7 @@
             <constraint name="Magento\Ui\Test\Constraint\AssertGridFiltering"/>
         </variation>
         <variation name="SalesCreditMemoGridFiltering">
+            <data name="tag" xsi:type="string">severity:S3</data>
             <data name="description" xsi:type="string">Verify sales credit memo grid filtering</data>
             <data name="steps" xsi:type="array">
                 <item name="0" xsi:type="array">
diff --git a/dev/tests/functional/tests/app/Magento/Sales/Test/TestCase/GridFullTextSearchTest.xml b/dev/tests/functional/tests/app/Magento/Sales/Test/TestCase/GridFullTextSearchTest.xml
index 0979d0dcbff250a7f0bdb2d5151f60004f72efd0..86278c52a1e26f28c82b799de7a1f45a1f4273e9 100644
--- a/dev/tests/functional/tests/app/Magento/Sales/Test/TestCase/GridFullTextSearchTest.xml
+++ b/dev/tests/functional/tests/app/Magento/Sales/Test/TestCase/GridFullTextSearchTest.xml
@@ -8,7 +8,7 @@
 <config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../../../../../../vendor/magento/mtf/etc/variations.xsd">
     <testCase name="Magento\Ui\Test\TestCase\GridFullTextSearchTest" summary="Grid UI Component Full Text Search" ticketId="MAGETWO-41023">
         <variation name="SalesOrderGridFullTextSearch">
-            <data name="tag" xsi:type="string">stable:no</data>
+            <data name="tag" xsi:type="string">severity:S2, stable:no</data>
             <data name="description" xsi:type="string">Verify sales order grid full text search</data>
             <data name="steps" xsi:type="array">
                 <item name="0" xsi:type="string">-</item>
@@ -24,7 +24,7 @@
             <constraint name="Magento\Ui\Test\Constraint\AssertGridFullTextSearch"/>
         </variation>
         <variation name="SalesInvoiceGridFullTextSearch">
-            <data name="tag" xsi:type="string">stable:no</data>
+            <data name="tag" xsi:type="string">severity:S3, stable:no</data>
             <data name="description" xsi:type="string">Verify sales invoice grid full text search</data>
             <data name="steps" xsi:type="array">
                 <item name="0" xsi:type="string">Magento\Sales\Test\TestStep\CreateInvoiceStep</item>
@@ -41,6 +41,7 @@
             <constraint name="Magento\Ui\Test\Constraint\AssertGridFullTextSearch"/>
         </variation>
         <variation name="SalesShipmentGridFullTextSearch">
+            <data name="tag" xsi:type="string">severity:S3</data>
             <data name="description" xsi:type="string">Verify sales shipment grid full text search</data>
             <data name="steps" xsi:type="array">
                 <item name="0" xsi:type="string">Magento\Sales\Test\TestStep\CreateShipmentStep</item>
@@ -57,7 +58,7 @@
             <constraint name="Magento\Ui\Test\Constraint\AssertGridFullTextSearch"/>
         </variation>
         <variation name="SalesCreditMemoGridFullTextSearch">
-            <data name="tag" xsi:type="string">stable:no</data>
+            <data name="tag" xsi:type="string">severity:S3, stable:no</data>
             <data name="description" xsi:type="string">Verify sales credit memo grid full text search</data>
             <data name="steps" xsi:type="array">
                 <item name="0" xsi:type="array">
diff --git a/dev/tests/functional/tests/app/Magento/Sales/Test/TestCase/GridSortingTest.xml b/dev/tests/functional/tests/app/Magento/Sales/Test/TestCase/GridSortingTest.xml
index f82f232625841ddfdd77e66812970a4de31efea6..75d5c7fd09d95200255119b7b00c7167eb8c0142 100644
--- a/dev/tests/functional/tests/app/Magento/Sales/Test/TestCase/GridSortingTest.xml
+++ b/dev/tests/functional/tests/app/Magento/Sales/Test/TestCase/GridSortingTest.xml
@@ -8,6 +8,7 @@
 <config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../../../../../../vendor/magento/mtf/etc/variations.xsd">
     <testCase name="Magento\Ui\Test\TestCase\GridSortingTest" summary="Grid UI Component Sorting" ticketId="MAGETWO-41328">
         <variation name="SalesOrderGridSorting">
+            <data name="tag" xsi:type="string">severity:S2</data>
             <data name="tag" xsi:type="string">to_maintain:yes</data>
             <data name="description" xsi:type="string">Verify sales order grid storting</data>
             <data name="steps" xsi:type="array">
@@ -27,6 +28,7 @@
             <constraint name="\Magento\Ui\Test\Constraint\AssertGridSorting"/>
         </variation>
         <variation name="SalesInvoiceGridSorting">
+            <data name="tag" xsi:type="string">severity:S3</data>
             <data name="tag" xsi:type="string">to_maintain:yes</data>
             <data name="description" xsi:type="string">Verify sales invoince grid storting</data>
             <data name="steps" xsi:type="array">
@@ -45,6 +47,7 @@
             <constraint name="\Magento\Ui\Test\Constraint\AssertGridSorting"/>
         </variation>
         <variation name="SalesShipmentGridSorting">
+            <data name="tag" xsi:type="string">severity:S3</data>
             <data name="tag" xsi:type="string">to_maintain:yes</data>
             <data name="description" xsi:type="string">Verify sales shipment grid storting</data>
             <data name="steps" xsi:type="array">
@@ -63,6 +66,7 @@
             <constraint name="\Magento\Ui\Test\Constraint\AssertGridSorting"/>
         </variation>
         <variation name="SalesCreditMemoGridSorting">
+            <data name="tag" xsi:type="string">severity:S3</data>
             <data name="tag" xsi:type="string">to_maintain:yes</data>
             <data name="description" xsi:type="string">Verify sales credit memo grid storting</data>
             <data name="steps" xsi:type="array">
diff --git a/dev/tests/functional/tests/app/Magento/Ui/Test/TestCase/GridFilteringTest.php b/dev/tests/functional/tests/app/Magento/Ui/Test/TestCase/GridFilteringTest.php
index 4b923dd4344a93be0e2bf3491c30eecf823f76ba..7a3da9b3fa7cd1d74bf0cc707f8b0be2ddc1214e 100644
--- a/dev/tests/functional/tests/app/Magento/Ui/Test/TestCase/GridFilteringTest.php
+++ b/dev/tests/functional/tests/app/Magento/Ui/Test/TestCase/GridFilteringTest.php
@@ -28,6 +28,7 @@ use Magento\Ui\Test\Block\Adminhtml\DataGrid;
 class GridFilteringTest extends Injectable
 {
     /* tags */
+    const SEVERITY = 'S2';
     const STABLE = 'no';
     const MVP = 'no';
     /* end tags */
diff --git a/dev/tests/functional/tests/app/Magento/Ui/Test/TestCase/GridFullTextSearchTest.php b/dev/tests/functional/tests/app/Magento/Ui/Test/TestCase/GridFullTextSearchTest.php
index 510d2d61c0acd2100b295ee1422015b1833d9c36..a16d61e112a83a2b008f49d9b95e072aec06d7ec 100644
--- a/dev/tests/functional/tests/app/Magento/Ui/Test/TestCase/GridFullTextSearchTest.php
+++ b/dev/tests/functional/tests/app/Magento/Ui/Test/TestCase/GridFullTextSearchTest.php
@@ -28,6 +28,7 @@ use Magento\Ui\Test\Block\Adminhtml\DataGrid;
 class GridFullTextSearchTest extends Injectable
 {
     /* tags */
+    const SEVERITY = 'S2';
     const STABLE = 'no';
     const MVP = 'no';
     /* end tags */
diff --git a/dev/tests/functional/tests/app/Magento/Ui/Test/TestCase/GridSortingTest.php b/dev/tests/functional/tests/app/Magento/Ui/Test/TestCase/GridSortingTest.php
index d1f543c7b989137c209bdbd63e6c4755644e9e8b..319ef215bcb142677d847a2c3e6ce0af6ba80199 100644
--- a/dev/tests/functional/tests/app/Magento/Ui/Test/TestCase/GridSortingTest.php
+++ b/dev/tests/functional/tests/app/Magento/Ui/Test/TestCase/GridSortingTest.php
@@ -28,6 +28,7 @@ use Magento\Ui\Test\Block\Adminhtml\DataGrid;
 class GridSortingTest extends Injectable
 {
     /* tags */
+    const SEVERITY = 'S2';
     const MVP = 'no';
     /* end tags */
 
diff --git a/dev/tests/functional/tests/app/Magento/Ui/Test/etc/di.xml b/dev/tests/functional/tests/app/Magento/Ui/Test/etc/di.xml
new file mode 100644
index 0000000000000000000000000000000000000000..8982c1966306252a5d0113ac49e8efdb011e8ddb
--- /dev/null
+++ b/dev/tests/functional/tests/app/Magento/Ui/Test/etc/di.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+/**
+ * Copyright © 2016 Magento. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+ -->
+<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
+    <type name="Magento\Ui\Test\Constraint\AssertGridFiltering">
+        <arguments>
+            <argument name="severity" xsi:type="string">S2</argument>
+        </arguments>
+    </type>
+    <type name="Magento\Ui\Test\Constraint\AssertGridFullTextSearch">
+        <arguments>
+            <argument name="severity" xsi:type="string">S2</argument>
+        </arguments>
+    </type>
+    <type name="Magento\Ui\Test\Constraint\AssertGridSorting">
+        <arguments>
+            <argument name="severity" xsi:type="string">S2</argument>
+        </arguments>
+    </type>
+</config>
diff --git a/lib/internal/Magento/Framework/View/Asset/MergeStrategy/Checksum.php b/lib/internal/Magento/Framework/View/Asset/MergeStrategy/Checksum.php
index bfdd516de7e366a3df4773776abec8e118b3916f..44b5bb65c49d36f690490e130f68c3868f162ce6 100644
--- a/lib/internal/Magento/Framework/View/Asset/MergeStrategy/Checksum.php
+++ b/lib/internal/Magento/Framework/View/Asset/MergeStrategy/Checksum.php
@@ -6,6 +6,8 @@
 namespace Magento\Framework\View\Asset\MergeStrategy;
 
 use Magento\Framework\App\Filesystem\DirectoryList;
+use Magento\Framework\App\ObjectManager;
+use Magento\Framework\View\Asset\Source;
 
 /**
  * Skip merging if all of the files that need to be merged were not modified
@@ -25,6 +27,11 @@ class Checksum implements \Magento\Framework\View\Asset\MergeStrategyInterface
      */
     protected $filesystem;
 
+    /**
+     * @var Source
+     */
+    private $assetSource;
+
     /**
      * @param \Magento\Framework\View\Asset\MergeStrategyInterface $strategy
      * @param \Magento\Framework\Filesystem $filesystem
@@ -37,17 +44,31 @@ class Checksum implements \Magento\Framework\View\Asset\MergeStrategyInterface
         $this->filesystem = $filesystem;
     }
 
+    /**
+     * @deprecated
+     * @return Source
+     */
+    private function getAssetSource()
+    {
+        if (!$this->assetSource) {
+            $this->assetSource = ObjectManager::getInstance()->get(Source::class);
+        }
+        return $this->assetSource;
+    }
+
     /**
      * {@inheritdoc}
      */
     public function merge(array $assetsToMerge, \Magento\Framework\View\Asset\LocalInterface $resultAsset)
     {
-        $sourceDir = $this->filesystem->getDirectoryRead(DirectoryList::ROOT);
+        $rootDir = $this->filesystem->getDirectoryRead(DirectoryList::ROOT);
         $mTime = null;
         /** @var \Magento\Framework\View\Asset\MergeableInterface $asset */
         foreach ($assetsToMerge as $asset) {
-            $mTime .= $sourceDir->stat($sourceDir->getRelativePath($asset->getSourceFile()))['mtime'];
+            $sourceFile = $this->getAssetSource()->findSource($asset);
+            $mTime .= $rootDir->stat($rootDir->getRelativePath($sourceFile))['mtime'];
         }
+
         if (null === $mTime) {
             return; // nothing to merge
         }
diff --git a/lib/internal/Magento/Framework/View/Test/Unit/Asset/MergeStrategy/ChecksumTest.php b/lib/internal/Magento/Framework/View/Test/Unit/Asset/MergeStrategy/ChecksumTest.php
index 9c7859116c4cbcc3da0947e6a39e5f1295dc4a8b..b20420640ebe42b31472299b2879f2f13f6abbe1 100644
--- a/lib/internal/Magento/Framework/View/Test/Unit/Asset/MergeStrategy/ChecksumTest.php
+++ b/lib/internal/Magento/Framework/View/Test/Unit/Asset/MergeStrategy/ChecksumTest.php
@@ -8,6 +8,7 @@ namespace Magento\Framework\View\Test\Unit\Asset\MergeStrategy;
 use \Magento\Framework\View\Asset\MergeStrategy\Checksum;
 
 use Magento\Framework\App\Filesystem\DirectoryList;
+use Magento\Framework\View\Asset\Source;
 
 class ChecksumTest extends \PHPUnit_Framework_TestCase
 {
@@ -31,6 +32,11 @@ class ChecksumTest extends \PHPUnit_Framework_TestCase
      */
     private $resultAsset;
 
+    /**
+     * @var Source|\PHPUnit_Framework_MockObject_MockObject
+     */
+    private $assetSource;
+
     /**
      * @var \Magento\Framework\View\Asset\MergeStrategy\Checksum
      */
@@ -53,6 +59,15 @@ class ChecksumTest extends \PHPUnit_Framework_TestCase
             ->with(DirectoryList::STATIC_VIEW)
             ->will($this->returnValue($this->targetDir));
         $this->checksum = new Checksum($this->mergerMock, $filesystem);
+        $this->assetSource = $this->getMockBuilder(Source::class)
+            ->disableOriginalConstructor()
+            ->getMock();
+
+        $reflection = new \ReflectionClass(Checksum::class);
+        $reflectionProperty = $reflection->getProperty('assetSource');
+        $reflectionProperty->setAccessible(true);
+        $reflectionProperty->setValue($this->checksum, $this->assetSource);
+
         $this->resultAsset = $this->getMock(\Magento\Framework\View\Asset\File::class, [], [], '', false);
     }
 
@@ -114,9 +129,17 @@ class ChecksumTest extends \PHPUnit_Framework_TestCase
     private function getAssetsToMerge()
     {
         $one = $this->getMock(\Magento\Framework\View\Asset\File::class, [], [], '', false);
-        $one->expects($this->once())->method('getSourceFile')->will($this->returnValue('/dir/file/one.txt'));
         $two = $this->getMock(\Magento\Framework\View\Asset\File::class, [], [], '', false);
-        $two->expects($this->once())->method('getSourceFile')->will($this->returnValue('/dir/file/two.txt'));
+        $one->expects($this->never())
+            ->method('getSourceFile');
+        $two->expects($this->never())
+            ->method('getSourceFile');
+
+        $this->assetSource->expects($this->exactly(2))
+            ->method('findSource')
+            ->withConsecutive([$one], [$two])
+            ->willReturnOnConsecutiveCalls('/dir/file/one.txt', '/dir/file/two.txt');
+
         $this->sourceDir->expects($this->exactly(2))
             ->method('getRelativePath')
             ->will($this->onConsecutiveCalls('file/one.txt', 'file/two.txt'));