Magento 1 - Module Unit Testing

Helper.php

<?php

class Some_Module_Helper_Data extends Mage_Core_Helper_Abstract
{
    /**
     * This method interacts with the database, so it will be mocked for the unit test.
     */
    public function queryDatabase()
    {
        return $this->getSomeDbData();
    }

    /**
     * This method changes the data fetched from the DB. We will test its logic.
     *
     * @return integer
     */
    public function multiply()
    {
        $dbData = $this->queryDatabase();

        return $dbData * 10;
    }
}

install_phpunit.sh

#!/bin/bash

for i in $(seq 5 7);
do
    if ! type "phpunit$i" > /dev/null; then
        sudo wget -O /usr/local/bin/phpunit$i https://phar.phpunit.de/phpunit-$i.phar
        sudo chmod +x /usr/local/bin/phpunit$i 
        echo -e "Installed phpunit$i.\n"
    fi
done 

TestHelper.php

<?php

use PHPUnit\Framework\TestCase;

/**
 * To run the test suite: phpunit6 --colors=auto Test*
 */
class TestHelper extends TestCase
{
    public function setUp()
    {
        /**
         * We have to mock the parent class if we want to break the inheritance chain
         * and avoid loading the whole framework.
         *
         * See this comment by Sebastian Bergmann (creator of phpunit):
         * https://stackoverflow.com/a/28303890/7874784
         */
        $this->getMockBuilder('Mage_Core_Helper_Abstract')->getMock();

        /**
         * Now that we have mocked the parent, we can load the helper directly.
         */
        require_once dirname(__FILE__) . '/Helper.php';

        /**
         * We will replace the return value of queryDatabase during the test.
         */
        $this->helper = $this->getMockBuilder(Some_Module_Helper_Data::class)
            ->setMethods(['queryDatabase'])
            ->getMock();

    }

    /** @test */
    public function it_multiplies_the_db_data()
    {
        /**
         * Here we set the method queryDatabase() to return dummy data for our test,
         * then we test the logic inside the method multiply().
         */
        $this->helper->method('queryDatabase')->willReturn(5);

        $this->assertEquals(50, $this->helper->multiply());
    }
}