Fix variable name in test class too long

Author: Magently

lib/internal/Magento/Framework/Model/Test/Unit/ResourceModel/Db/Collection/AbstractCollectionTest.php

@@ -267,10 +267,10 @@ public function addFieldToSelectDataProvider()
     /**
      * @dataProvider addExpressionFieldToSelectDataProvider
      */
-    public function testAddExpressionFieldToSelect($alias, $expression, $fields, $expectedFieldsToSelect)
+    public function testAddExpressionFieldToSelect($alias, $expression, $fields, $expected)
     {
         $this->assertTrue($this->uut->addExpressionFieldToSelect($alias, $expression, $fields) instanceof Uut);
-        $this->assertEquals($expectedFieldsToSelect, $this->uut->getFieldsToSelect());
+        $this->assertEquals($expected, $this->uut->getFieldsToSelect());
         $this->assertTrue($this->uut->wereFieldsToSelectChanged());
     }