PHP PHPUnit Test Cases

Write a class ‘Skill’ that handles any function which starts with ‘has_’ keyword return function ‘exist’ and any other function that starts with any word that should return ‘not exist’ and checking a property if it ends with ‘_CT’ return md5 encryption for property otherwise return without encryption.

I have used magic functions and object-oriented programming.

Below are the files with the code for class Skill and test cases:

Skill.php

<?php declare(strict_types=1);

namespace Exam;

class Skill
{
    public function __call($name, $arguments)
    {
        if (strpos($name, 'has_') === 0) {
            return 'exist';
        } else {
            return 'not exist';
        }
    }

    public function __get($name)
    {
        if (substr($name, -3) === '_CT') {
            return md5($name);
        } else {
            return 'not exist';
        }
    }

    public function __toString()
    {
        return 'Skill object';
    }

    public function __set($name, $value)
    {
        $this->$name = $value;
    }

    public function __invoke($args)
    {
        return array_sum($args);
    }
}

SkillTest.php

<?php

use CoalitionExamSkill;
use PHPUnitFrameworkTestCase;

class SkillTest extends TestCase
{
    public function testHasFunctionExists(): void
    {
        $skill = new Skill();
        $function = 'has' . $this->generateRandomString(5);
        $this->assertTrue($skill->$function(), 'success');
    }

    public function testHasPropertyExists(): void
    {
        $skill = new Skill();
        $property = $this->generateRandomString(7) . '_CT';

        $this->assertTrue($skill->$property == md5($property), 'success');
    }
     
    public function testHasAnyPropertyExists(): void
    {
        $skill = new Skill();
        $property = $this->generateRandomString(7);

        $this->assertFalse($skill->$property == md5($property), 'success');
    }

    public function testObjectAsString(): void
    {
        $skill = new Skill();
        $this->assertTrue( strpos($skill, 'CT') !== false, 'success');
    }

    public function testSetSkillLanguage(): void
    {
        $skill = new Skill();
        $skill->language = 'PHP';
        $this->assertTrue( $skill->language === 'PHP', 'success');
    }


    public function testInvoke(): void
    {
        $skill = new Skill();
        $this->assertEquals(10, $skill([3,7]));
    }

    private function generateRandomString($length = 10): string
    {
        $characters = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
        $charactersLength = strlen($characters);
        $randomString = '';
        for ($i = 0; $i < $length; $i++) {
            $randomString .= $characters[rand(0, $charactersLength - 1)];
        }
        return $randomString;
    }

}

When I run PHPUnit tests, I am getting 2 failures.

There were 2 failures:

1)

SkillTest::testHasFunctionExists
success
Failed asserting that ‘not exist’ is true.

C:xampphtdocsRizeen-CTtestsSkillTest.php:12

SkillTest::testObjectAsString
success
Failed asserting that false is true.

C:xampphtdocsRizeen-CTtestsSkillTest.php:34

FAILURES!

Tests: 6, Assertions: 6, Failures: 2.

I tried using assertFalse(), but the issue still persists.