MAGETWO-69521: Customer attribute with "Show on Storefront" set to No does not appear in backend

Author: Sergii Kovalenko

app/code/Magento/Customer/Test/Unit/Model/Customer/DataProviderTest.php

@@ -425,11 +425,7 @@ protected function getAttributeMock($type = 'customer', $options = [])
 
         $attributeMock->expects($this->any())
             ->method('getDataUsingMethod')
-            ->willReturnCallback(
-                function ($origName) {
-                    return $origName;
-                }
-            );
+            ->willReturnCallback($this->attributeGetUsingMethodCallback());
 
         $attributeMock->expects($this->any())
             ->method('usesSource')
@@ -460,11 +456,7 @@ function ($origName) {
             ->willReturn('boolean');
         $attributeBooleanMock->expects($this->any())
             ->method('getDataUsingMethod')
-            ->willReturnCallback(
-                function ($origName) {
-                    return $origName;
-                }
-            );
+            ->willReturnCallback($this->attributeGetUsingMethodCallback());
 
         $attributeBooleanMock->expects($this->once())
             ->method('usesSource')
@@ -492,6 +484,18 @@ function ($origName) {
         return $mocks;
     }
 
+    /**
+     * Callback for ::getDataUsingMethod
+     *
+     * @return \Closure
+     */
+    private function attributeGetUsingMethodCallback()
+    {
+        return function ($origName) {
+            return $origName;
+        };
+    }
+
     private function getCountryAttrMock()
     {
         $countryByWebsiteMock = $this->getMockBuilder(CountryWithWebsites::class)