datatable.directory/tests/Unit/ColumnNumeratorTest.php

<?php

namespace Tests\Unit;

use App\Tables\ColumnNumerator;
use Tests\TestCase;
use Illuminate\Foundation\Testing\RefreshDatabase;

class ColumnNumeratorTest extends TestCase
{
    public function testIncrementsWithDefaultInit()
    {
        $n = new ColumnNumerator();

        self::assertEquals('a', $n->next());
        self::assertEquals('b', $n->next());
        self::assertEquals('c', $n->next());
    }

    public function testIncrementsWithCustomInit()
    {
        $n = new ColumnNumerator('r');

        self::assertEquals('r', $n->next());
        self::assertEquals('s', $n->next());
        self::assertEquals('t', $n->next());
    }

    public function testIncrementsMultiChar()
    {
        $n = new ColumnNumerator('aaa');

        self::assertEquals('aaa', $n->next());
        self::assertEquals('aab', $n->next());
        self::assertEquals('aac', $n->next());
    }

    public function testOverflowGrow()
    {
        $n = new ColumnNumerator('y');

        self::assertEquals('y', $n->next());
        self::assertEquals('z', $n->next());
        self::assertEquals('aa', $n->next());
        self::assertEquals('ab', $n->next());
    }

    public function testOverflowNoGrow()
    {
        $n = new ColumnNumerator('yy');

        self::assertEquals('yy', $n->next());
        self::assertEquals('yz', $n->next());
        self::assertEquals('za', $n->next());
        self::assertEquals('zb', $n->next());
    }

    public function testResume()
    {
        $n = new ColumnNumerator('yy');
        self::assertEquals('yy', $n->next());
        self::assertEquals('yz', $n->next());

        $n2 = new ColumnNumerator($n->getState());
        unset($n);

        self::assertEquals('za', $n2->next(), 'recreated numerator continues');
        self::assertEquals('zb', $n2->next());

        self::assertEquals($n2->getState(), 'zc', 'State is next string');
    }
}