More Coverage In Unit Tests (#3447)

* More Coverage In Unit Tests

Minimal source code changes.

* Scrutinizer

One legitimate complaint and one from out of left field.

* Scrutinizer Lunacy

If this doesn't stop its complaint, I give up.

* Scrutinizer - Whatever

Try again.

* Glutton For Punishment

Try again.

tests/PhpSpreadsheetTests/ReferenceHelperTest.php

@@ -16,10 +16,6 @@ use PHPUnit\Framework\TestCase;
 
 class ReferenceHelperTest extends TestCase
 {
-    protected function setUp(): void
-    {
-    }
-
     public function testColumnSort(): void
     {
         $columnBase = $columnExpectedResult = [