PHP ライブラリを作成してテストするにはどうすればよいですか?

<?php

function addNumbers($num1, $num2)
{
    return $num1 + $num2;
}

?>

<?php

require 'my_functions.php';

?>

<?php

$num1 = 10;
$num2 = 5;
$expectedSum = 15;

$sum = addNumbers($num1, $num2);

if ($sum === $expectedSum) {
    echo "Pass" . PHP_EOL;
} else {
    echo "Fail" . PHP_EOL;
}

?>

php test_my_functions.php

Pass

// my_geometry_functions.php

<?php

function calculateAreaSquare($sideLength)
{
    return $sideLength * $sideLength;
}

function calculateAreaRectangle($length, $width)
{
    return $length * $width;
}

function calculateAreaCircle($radius)
{
    return pi() * ($radius * $radius);
}

?>

// test_my_geometry_functions.php

<?php

require 'my_geometry_functions.php';

$sideLength = 5;
$expectedAreaSquare = 25;

$areaSquare = calculateAreaSquare($sideLength);

if ($areaSquare === $expectedAreaSquare) {
    echo "Pass: Square" . PHP_EOL;
} else {
    echo "Fail: Square" . PHP_EOL;
}

$length = 10;
$width = 5;
$expectedAreaRectangle = 50;

$areaRectangle = calculateAreaRectangle($length, $width);

if ($areaRectangle === $expectedAreaRectangle) {
    echo "Pass: Rectangle" . PHP_EOL;
} else {
    echo "Fail: Rectangle" . PHP_EOL;
}

$radius = 3;
$expectedAreaCircle = 28.27;

$areaCircle = calculateAreaCircle($radius);

if (abs($areaCircle - $expectedAreaCircle) <= 0.01) {
    echo "Pass: Circle" . PHP_EOL;
} else {
    echo "Fail: Circle" . PHP_EOL;
}

?>