Add test to uncover glob pattern not being applied

The Magento\Ui\DataProvider\Config\FileResolver does not apply the
filename glob pattern passed to the method while matching files.
This test triggers the error.

Author: Vinai

dev/tests/unit/testsuite/Magento/Ui/DataProvider/Config/FileResolverTest.php

@@ -0,0 +1,50 @@
+<?php
+
+namespace Magento\Ui\DataProvider\Config;
+
+use Magento\Framework\Filesystem;
+use Magento\Ui\DataProvider\Config\FileResolver;
+use Magento\Framework\Config\FileIteratorFactory;
+
+class FileResolverTest extends \PHPUnit_Framework_TestCase
+{
+    /**
+     * @var \Magento\Framework\Filesystem\Directory\Read | \PHPUnit_Framework_MockObject_MockObject
+     */
+    private $mockDirectoryRead;
+
+    /**
+     * @var FileResolver
+     */
+    private $fileResolver;
+
+    public function setUp()
+    {
+        $this->mockDirectoryRead = $this->getMockBuilder('Magento\Framework\Filesystem\Directory\Read')
+            ->disableOriginalConstructor()
+            ->getMock();
+        $stubFileIteratorFactory = $this->getMockBuilder('Magento\Framework\Config\FileIteratorFactory')
+            ->disableOriginalConstructor()
+            ->getMock();
+        $stubFilesystem = $this->getMockBuilder('Magento\Framework\Filesystem')
+            ->disableOriginalConstructor()
+            ->getMock();
+        $stubFilesystem->expects($this->any())
+            ->method('getDirectoryRead')
+            ->willReturn($this->mockDirectoryRead);
+        $this->fileResolver = new FileResolver($stubFilesystem, $stubFileIteratorFactory);
+    }
+
+    /**
+     * @test
+     */
+    public function itShouldApplyTheFilenamePattern()
+    {
+        $this->mockDirectoryRead->expects($this->once())
+            ->method('search')
+            ->with($this->matchesRegularExpression('#\*\.xml$#'))
+            ->willReturn([]);
+        
+        $this->fileResolver->get('*.xml', '');
+    }
+}