formatting numbers to an arbitrary number of decimals while removing zeroes

SomethingTest.php

<?php declare(strict_types=1);

namespace Test;

use PHPUnit\Framework\TestCase;

/*
 * We want to format numbers with , as decimal separator and space as thousand separator
 * removing any trailling 0
 * and any excedent decimals past a certain number
 *
 * we assume that the number separator is always .
 *
 */

function format(string $number, int $decimal = 0): string
{
    if (strpos($number, '.') === false) {
        return makeNumber($number);
    }

    [$whole, $fraction] = explode('.', $number);

    return makeNumber($whole) . ($fraction > 0 ? (',' . makeDecimals($fraction, $decimal)) : '');
}

function makeDecimals(string $decimals, int $limit): string
{
    if (\strlen($decimals) === 0) {
        throw new \LogicException('we are formatting an empty string');
    }
    return substr(rtrim($decimals, '0'), 0, $limit);
}

function makeNumber(string $number): string
{
    return ltrim(strrev(chunk_split(strrev($number), 3, ' ')), ' ');
}

class SomethingTest extends TestCase
{
    /** @test */
    public function basic_stuff(): void
    {
        $this->assertSame(1.04, (float)'1.04');
    }

    /** @test */
    public function trims_decimals(): void
    {
        $this->assertSame('003', makeDecimals('0030', 3));
        $this->assertSame('003', makeDecimals('0030', 4));
        $this->assertSame('0034', makeDecimals('00345', 4));
    }

    /** @test */
    public function spaces_number(): void
    {
        $this->assertSame('1 300', makeNumber('1300'));
        $this->assertSame('300', makeNumber('300'));
    }

    /** @test */
    public function pads_stuff(): void
    {
        $this->assertSame('1', format('1.00', 2));
        $this->assertSame('1', format('1.00', 4));
        $this->assertSame('0,25', format('0.25', 4));
        $this->assertSame('1 000,25', format('1000.25', 4));
        $this->assertSame('1,044', format('1.044', 3));
        $this->assertSame('0,24', format('0.24000', 5));
        $this->assertSame('0,24546', format('0.24546', 5));
        $this->assertSame('0,2454', format('0.24546', 4));
        $this->assertSame('6 500', format('6500.00', 0));
        $this->assertSame('3 760,54', format('3760.54', 2));
        $this->assertSame('3 760,54', format('3760.541234', 2));
        $this->assertSame('3 760', format('3760.00', 2));
    }
}