silverstripe-framework/tests/php/ORM/DBYearTest.php

<?php

namespace SilverStripe\ORM\Tests;

use SilverStripe\Forms\DropdownField;
use SilverStripe\ORM\FieldType\DBYear;
use SilverStripe\Dev\SapphireTest;

class DBYearTest extends SapphireTest
{

    /**
     * Test that the scaffolding form field works
     */
    public function testScaffoldFormFieldFirst()
    {
        $year = new DBYear();
        $field = $year->scaffoldFormField("YearTest");
        $this->assertEquals(DropdownField::class, get_class($field));

        //This should be a list of years from the current one, counting down to 1900
        $source = $field->getSource();

        $lastValue = end($source);
        $lastKey = key($source ?? []);

        //Keys and values should be the same - and the last one should be 1900
        $this->assertEquals(1900, $lastValue);
        $this->assertEquals(1900, $lastKey);
    }

    public function testScaffoldFormFieldLast()
    {
        $year = new DBYear();
        $field = $year->scaffoldFormField("YearTest");
        $source = $field->getSource();

        //The first one should be the current year
        $currentYear = (int)date('Y');
        $firstValue = reset($source);
        $firstKey = key($source ?? []);

        $this->assertEquals($currentYear, $firstValue);
        $this->assertEquals($currentYear, $firstKey);
    }
}