What's Test Spy?

ApplicationTest.php

<?php
namespace Example\Application\Tests;

use \Example\Application;

use \SymfonyX\Component\Console\Output\SpyOutput;

class ApplicationTest extends \PHPUnit_Framework_TestCase
{
    private $app;

    private $spy;

    public function setUp()
    {
        $this->spy = new SpyOutput;
        $this->app = new Application($this->spy);
    }

    public function testAppOutputsCorrectly()
    {
        $this->app->run();
        $this->assertEquals('Hello, World!' . PHP_EOL, $this->spy->getMessage());
    }
}

ProgressTest.php

<?php
namespace ExampleApp\Tests;

use \ExampleApp\Progress;

use \SymfonyX\Component\Console\Output\SpyOutput;

class ProgressTest extends \PHPUnit_Framework_TestCase
{
    public function test_progress_works_correctly()
    {
        $expected = <<< __EOF__
[  0%]   0/100
[ 10%]  10/100
[ 20%]  20/100
[ 30%]  30/100
[ 40%]  40/100
[ 50%]  50/100
[ 60%]  60/100
[ 70%]  70/100
[ 80%]  80/100
[ 90%]  90/100
[100%] 100/100

__EOF__;

        $spy = new SpyOutput;
        $progress = new Progress(100, $spy);
        for ($i = 0; $i < 100; $i++) {
            $progress->setCurrentPosition($i);
        }

        $this->assertEquals($expected, $spy->getMessage());
    }
}

SomeCommand.php

<?php
namespace ExampleApp\Command;

use \ExampleApp\Progress;

use \Symfony\Component\Console\Command\Command,
    \Symfony\Component\Console\Input\InputInterface,
    \Symfony\Component\Console\Output\OutputInterface;

class ExecuteCommand extends Command
{
    public function execute(InputInterface $input, OutputInterface $output)
    {
        $records = findRecords();
        $progress = new Progress(count($records), $output);
        foreach ($records as $i => $record) {
            $progress->setCurrentPosition($i);
        }
    }
}

Great, thanks!

The issue of application safety is very relevant for me now. I really want to install a spy app on my wife's phone, I studied everything in detail on this source realspyapps.com/review/pctattletale/ and I think that there should be no problems with installation, but I'm very afraid that she will be able to notice the appearance of a spy on her phone. Anyone faced a similar situation? Do spy apps really work discreetly and safely?