diff --git a/.env b/.env
index fb05b5f..53ea551 100644
--- a/.env
+++ b/.env
@@ -1,5 +1,5 @@
 ###> mediashare/time-tracking ###
-APP_VERSION=0.4.0
+APP_VERSION=0.4.2
 ###< mediashare/time-tracking ###
 
 ###> symfony/framework-bundle ###
diff --git a/.env.local.php b/.env.local.php
index d377ce9..87f4360 100644
--- a/.env.local.php
+++ b/.env.local.php
@@ -1,9 +1,9 @@
 <?php
 
-// This file was generated by running "composer dump-env prod"
+// This file was generated by running "composer dump-env dev"
 
 return array (
-  'APP_ENV' => 'prod',
-  'APP_VERSION' => '0.4.0',
+  'APP_ENV' => 'dev',
+  'APP_VERSION' => '0.4.2',
   'APP_SECRET' => '91739cd3f0af5ce014a7db0d451160e2805aa31b',
 );
diff --git a/.env.test b/.env.test
new file mode 100644
index 0000000..9e7162f
--- /dev/null
+++ b/.env.test
@@ -0,0 +1,6 @@
+# define your env variables for the test env here
+KERNEL_CLASS='App\Kernel'
+APP_SECRET='$ecretf0rt3st'
+SYMFONY_DEPRECATIONS_HELPER=999999
+PANTHER_APP_ENV=panther
+PANTHER_ERROR_SCREENSHOT_DIR=./var/error-screenshots
diff --git a/.gitignore b/.gitignore
index 287225f..c67b3e5 100644
--- a/.gitignore
+++ b/.gitignore
@@ -13,3 +13,13 @@ symfony.lock
 .vscode
 .idea
 ###< mediashare/time-tracking ###
+
+###> symfony/phpunit-bridge ###
+.phpunit.result.cache
+/phpunit.xml
+###< symfony/phpunit-bridge ###
+
+###> phpunit/phpunit ###
+/phpunit.xml
+.phpunit.result.cache
+###< phpunit/phpunit ###
diff --git a/bin/phpunit b/bin/phpunit
new file mode 100644
index 0000000..692bacc
--- /dev/null
+++ b/bin/phpunit
@@ -0,0 +1,23 @@
+#!/usr/bin/env php
+<?php
+
+if (!ini_get('date.timezone')) {
+    ini_set('date.timezone', 'UTC');
+}
+
+if (is_file(dirname(__DIR__).'/vendor/phpunit/phpunit/phpunit')) {
+    if (PHP_VERSION_ID >= 80000) {
+        require dirname(__DIR__).'/vendor/phpunit/phpunit/phpunit';
+    } else {
+        define('PHPUNIT_COMPOSER_INSTALL', dirname(__DIR__).'/vendor/autoload.php');
+        require PHPUNIT_COMPOSER_INSTALL;
+        PHPUnit\TextUI\Command::main();
+    }
+} else {
+    if (!is_file(dirname(__DIR__).'/vendor/symfony/phpunit-bridge/bin/simple-phpunit.php')) {
+        echo "Unable to find the `simple-phpunit.php` script in `vendor/symfony/phpunit-bridge/bin/`.\n";
+        exit(1);
+    }
+
+    require dirname(__DIR__).'/vendor/symfony/phpunit-bridge/bin/simple-phpunit.php';
+}
diff --git a/composer.json b/composer.json
index 00d8a00..5bbe6be 100644
--- a/composer.json
+++ b/composer.json
@@ -92,5 +92,11 @@
         "time-tracking": {
             "console": "bin/time-tracking"
         }
+    },
+    "require-dev": {
+        "phpunit/phpunit": "^9.5",
+        "symfony/browser-kit": "^6.4",
+        "symfony/css-selector": "^6.4",
+        "symfony/phpunit-bridge": "^7.0"
     }
 }
diff --git a/config/bootstrap.php b/config/bootstrap.php
deleted file mode 100644
index 75bdee0..0000000
--- a/config/bootstrap.php
+++ /dev/null
@@ -1,23 +0,0 @@
-<?php
-
-use Symfony\Component\Dotenv\Dotenv;
-
-require dirname(__DIR__).'/vendor/autoload.php';
-
-// Load cached env vars if the .env.local.php file exists
-// Run "composer dump-env prod" to create it (requires symfony/flex >=1.2)
-if (is_array($env = @include dirname(__DIR__).'/.env.local.php') && ($_SERVER['APP_ENV'] ?? $_ENV['APP_ENV'] ?? $env['APP_ENV']) === $env['APP_ENV']) {
-    foreach ($env as $k => $v) {
-        $_ENV[$k] = $_ENV[$k] ?? (isset($_SERVER[$k]) && 0 !== strpos($k, 'HTTP_') ? $_SERVER[$k] : $v);
-    }
-} elseif (!class_exists(Dotenv::class)) {
-    throw new RuntimeException('Please run "composer require symfony/dotenv" to load the ".env" files configuring the application.');
-} else {
-    // load all the .env files
-    (new Dotenv(false))->loadEnv(dirname(__DIR__).'/.env.local.php');
-}
-
-$_SERVER += $_ENV;
-$_SERVER['APP_ENV'] = $_ENV['APP_ENV'] = ($_SERVER['APP_ENV'] ?? $_ENV['APP_ENV'] ?? null) ?: 'dev';
-$_SERVER['APP_DEBUG'] = $_SERVER['APP_DEBUG'] ?? $_ENV['APP_DEBUG'] ?? 'prod' !== $_SERVER['APP_ENV'];
-$_SERVER['APP_DEBUG'] = $_ENV['APP_DEBUG'] = (int) $_SERVER['APP_DEBUG'] || filter_var($_SERVER['APP_DEBUG'], FILTER_VALIDATE_BOOLEAN) ? '1' : '0';
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
new file mode 100644
index 0000000..c76a655
--- /dev/null
+++ b/phpunit.xml.dist
@@ -0,0 +1,38 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<!-- https://phpunit.readthedocs.io/en/latest/configuration.html -->
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:noNamespaceSchemaLocation="vendor/phpunit/phpunit/phpunit.xsd"
+         backupGlobals="false"
+         colors="true"
+         bootstrap="tests/bootstrap.php"
+         convertDeprecationsToExceptions="false"
+>
+    <php>
+        <ini name="display_errors" value="1" />
+        <ini name="error_reporting" value="-1" />
+        <server name="APP_ENV" value="test" force="true" />
+        <server name="SHELL_VERBOSITY" value="-1" />
+        <server name="SYMFONY_PHPUNIT_REMOVE" value="" />
+        <server name="SYMFONY_PHPUNIT_VERSION" value="9.6" />
+    </php>
+
+    <testsuites>
+        <testsuite name="Project Test Suite">
+            <directory>tests</directory>
+        </testsuite>
+    </testsuites>
+
+    <coverage processUncoveredFiles="true">
+        <include>
+            <directory suffix=".php">src</directory>
+        </include>
+    </coverage>
+
+    <listeners>
+        <listener class="Symfony\Bridge\PhpUnit\SymfonyTestsListener" />
+    </listeners>
+
+    <extensions>
+    </extensions>
+</phpunit>
diff --git a/src/Command/ArchiveCommand.php b/src/Command/ArchiveCommand.php
index 35ff172..72ed0b9 100644
--- a/src/Command/ArchiveCommand.php
+++ b/src/Command/ArchiveCommand.php
@@ -42,8 +42,8 @@ protected function execute(InputInterface $input, OutputInterface $output) {
             );
 
             // Tracking
-            $trackingService = new TrackingService($config);
-            $tracking = $trackingService->archiveTracking($input->getOption('stop'));
+            $trackingService = new TrackingService($config, createItIfNotExist: !$input->getOption('stop'));
+            $tracking = $trackingService->archiveTracking();
 
             // Update tracking data file
             $serializerService = new SerializerService();
@@ -66,9 +66,8 @@ protected function execute(InputInterface $input, OutputInterface $output) {
                 $input->getOption('config-datetime-format'),
                 $lastTrackingDirectory,
                 $config->getTrackingId() === $lastTrackingId
-                    ? (new \DateTime())->format(
-                    $input->getOption('config-datetime-format') ?? $configService->getLastDateTimeFormat()
-                    ) : $lastTrackingId
+                    ? (new \DateTime())->format('YmdHis')
+                    : $lastTrackingId
                 ,
             );
 
diff --git a/src/Command/RemoveCommand.php b/src/Command/RemoveCommand.php
index 35b484f..09e6458 100644
--- a/src/Command/RemoveCommand.php
+++ b/src/Command/RemoveCommand.php
@@ -40,7 +40,7 @@ protected function execute(InputInterface $input, OutputInterface $output) {
             );
 
             // Tracking
-            $trackingService = new TrackingService($config);
+            $trackingService = new TrackingService($config, createItIfNotExist: false);
             $tracking = $trackingService->getTracking(createItIfNotExist: false);
             $trackingService->removeTracking();
 
@@ -61,9 +61,8 @@ protected function execute(InputInterface $input, OutputInterface $output) {
                 $input->getOption('config-datetime-format'),
                 $lastTrackingDirectory,
                 $config->getTrackingId() === $lastTrackingId
-                    ? (new \DateTime())->format(
-                    $input->getOption('config-datetime-format') ?? $configService->getLastDateTimeFormat()
-                    ) : $lastTrackingId
+                    ? (new \DateTime())->format('YmdHis')
+                    : $lastTrackingId
                 ,
             );
 
diff --git a/src/Entity/Commit.php b/src/Entity/Commit.php
index f252bf8..b35c1d5 100644
--- a/src/Entity/Commit.php
+++ b/src/Entity/Commit.php
@@ -13,7 +13,7 @@ class Commit {
 
     private string|null $id = null;
     private string $message = '';
-    private string $duration = '00:00:00';
+
     private StepCollection $steps;
 
     public function __construct() {
diff --git a/src/Entity/Tracking.php b/src/Entity/Tracking.php
index 5c9da09..407a3d9 100644
--- a/src/Entity/Tracking.php
+++ b/src/Entity/Tracking.php
@@ -35,7 +35,7 @@ public function setId(string $id): self {
         return $this;
     }
 
-    public function getId(): string {
+    public function getId(): string|null {
         return $this->id;
     }
 
diff --git a/src/Service/CommitService.php b/src/Service/CommitService.php
index 2f6fbb9..72bc97a 100644
--- a/src/Service/CommitService.php
+++ b/src/Service/CommitService.php
@@ -28,6 +28,9 @@ public function createCommit(?string $message = null, ?string $duration = null):
             $commit->addStep(
                 $this->stepService->createStepWithCustomDuration(
                     $duration,
+                    ($lastStep = $this->tracking->getSteps()?->last())?->getEndDate()
+                        ? $lastStep->getStartDate()
+                        : null
                 )
             );
         else:
@@ -55,6 +58,9 @@ public function createCommit(?string $message = null, ?string $duration = null):
         return $this->tracking;
     }
 
+    /**
+     * @throws CommitNotFoundException
+     */
     public function editCommit(
         string $id,
         string|false $message = false,
@@ -102,6 +108,9 @@ public function editCommit(
         return $this->tracking;
     }
 
+    /**
+     * @throws CommitNotFoundException
+     */
     public function removeCommit(
         string $id,
     ): Tracking {
diff --git a/src/Service/ConfigService.php b/src/Service/ConfigService.php
index 4eae300..6fefa31 100644
--- a/src/Service/ConfigService.php
+++ b/src/Service/ConfigService.php
@@ -53,9 +53,19 @@ public function getLastTrackingDirectory(): string {
     }
 
     public function getLastTrackingId(string $trackingDirectory): string|null {
-        return $this->getLastConfig()->getTrackingId()
-            ?? (new TrackingService(new Config(trackingDirectory: $trackingDirectory)))->getTrackings()?->last()?->getId()
-            ;
+        try {
+            if ($lastTrackingIdByConfig = $this->getLastConfig()->getTrackingId()):
+                return $lastTrackingIdByConfig;
+            endif;
+
+            return (new TrackingService(new Config(trackingDirectory: $trackingDirectory)))
+                ->getTrackings()?->last()?->getId();
+
+        } catch (\Exception $exception) {
+
+        }
+
+        return null;
     }
 
     private function getLastConfig(): Config {
diff --git a/src/Service/SerializerService.php b/src/Service/SerializerService.php
index 47118dd..a3d90af 100644
--- a/src/Service/SerializerService.php
+++ b/src/Service/SerializerService.php
@@ -29,7 +29,9 @@ public function __construct() {
     }
 
     /**
-     * Convert json file to Tracking Object
+     * Convert json file to Entity object
+     * @throws FileNotFoundException
+     * @throws JsonDecodeException
      */
     public function read(string $filepath, string $className): Tracking|Config {
         if (!$this->filesystem->exists($filepath)):
diff --git a/src/Service/TrackingService.php b/src/Service/TrackingService.php
index 168aa56..7255a38 100644
--- a/src/Service/TrackingService.php
+++ b/src/Service/TrackingService.php
@@ -12,12 +12,19 @@
 class TrackingService {
     private SerializerService $serializerService;
     private Filesystem $filesystem;
+    private StepService $stepService;
+    private Tracking $tracking;
 
     public function __construct(
         private Config $config,
+        bool $createItIfNotExist = true
     ) {
         $this->serializerService = new SerializerService();
         $this->filesystem = new Filesystem();
+
+        $this->stepService = new StepService();
+
+        $this->tracking = $this->getTracking($createItIfNotExist);
     }
 
     /**
@@ -41,28 +48,24 @@ public function getTrackings(): TrackingCollection {
     public function getTracking(bool $createItIfNotExist = true): Tracking {
         $trackingExist = $this->filesystem->exists($filepath = $this->getTrackingFilepath());
         if (!$trackingExist && $createItIfNotExist):
-            return $this->createTracking();
+            return $this->tracking = $this->createTracking();
         elseif (!$trackingExist):
             throw new TrackingNotFoundException();
         endif;
 
-        return $this->serializerService->read($filepath, Tracking::class);
+        return $this->tracking = $this->serializerService->read($filepath, Tracking::class);
     }
 
     public function createTracking(array $data = []): Tracking {
-        if (!array_keys($data, 'id')):
-            $data = array_merge($data, [
-                'id' => $this->config->getTrackingId()
-                    ?? (new \DateTime())->format('YmdHis')
-            ]);
-        endif;
-
         /** @var Tracking $tracking */
         $tracking = $this->serializerService->arrayToEntity($data, Tracking::class);
 
+        if (!$tracking->getId()):
+            $tracking->setId($this->config->getTrackingId() ?? (new \DateTime())->format('YmdHis'));
+        endif;
+
         if ($tracking->isRun() && !$tracking->getSteps()?->last()?->getEndDate()):
-            $stepService = new StepService($tracking);
-            $tracking->addStep($stepService->createStep());
+            $tracking->addStep($this->stepService->createStep());
         endif;
 
         $this->serializerService->writeTracking($this->getTrackingFilepath(), $tracking);
@@ -72,27 +75,36 @@ public function createTracking(array $data = []): Tracking {
 
     public function startTracking(
         string|false $name = false,
-        string|null $duration = null,
+        string|false $duration = false,
     ): Tracking {
-        $tracking = $this->getTracking()->setRun(true);
+        $tracking = $this->tracking->setRun(true);
         $tracking->setName($name !== false ? $name : $tracking->getName());
 
+        if ($duration):
+            $firstStep = $tracking->getSteps()->first();
+            $tracking->getSteps()->clear();
+            $tracking->addStep($this
+                ->stepService
+                ->createStepWithCustomDuration(
+                    $duration,
+                    $firstStep?->getStartDate(),
+                )
+            );
+        endif;
+
         if (!$tracking->getStartDate() || !($lastStep = $tracking->getSteps()?->last()) || $lastStep->getEndDate()):
-            $stepService = new StepService();
             $tracking
                 ->addStep(
-                    $duration
-                        ? $stepService->createStepWithCustomDuration($duration)
-                        : $stepService->createStep()
+                    $this->stepService->createStep()
                 );
         endif;
 
         return $tracking;
     }
 
-    public function stopTracking(bool $createItIfNotExist = true): Tracking {
-        $tracking = $this->getTracking($createItIfNotExist);
-        $tracking->setRun(false);
+    public function stopTracking(): Tracking {
+        $tracking = $this->tracking
+            ->setRun(false);
 
         if (($lastStep = $tracking->getSteps()?->last()) && !$lastStep->getEndDate()):
             $tracking
@@ -106,10 +118,9 @@ public function stopTracking(bool $createItIfNotExist = true): Tracking {
         return $tracking;
     }
 
-    public function archiveTracking(bool $stop = false): Tracking {
-        $stop ? $this->stopTracking(createItIfNotExist: false) : null;
+    public function archiveTracking(): Tracking {
         return $this
-            ->getTracking()
+            ->stopTracking()
             ->setArchived(true);
     }
 
@@ -121,6 +132,9 @@ public function removeTracking(): self {
         return $this;
     }
 
+    /**
+     * @throws TrackingNotFoundException
+     */
     public function getTrackingFilepath(): string {
         if (!$this->config->getTrackingId()):
             throw new TrackingNotFoundException();
diff --git a/src/Trait/EntityDurationTrait.php b/src/Trait/EntityDurationTrait.php
index c1c334b..4714e2e 100644
--- a/src/Trait/EntityDurationTrait.php
+++ b/src/Trait/EntityDurationTrait.php
@@ -7,19 +7,19 @@
 use Mediashare\TimeTracking\Entity\Tracking;
 
 trait EntityDurationTrait {
-    private string $duration = '00:00:00';
-
     /**
      * Convert seconds to "d H:i:s" format
      */
     public function getDuration(bool|null $onlyNotCommited = false, int $totalSeconds = 0): string {
         $seconds = $this->getSeconds($onlyNotCommited) + $totalSeconds;
-        return $this->duration = sprintf(
-            '%s %02d:%02d:%02d',
-            ((($seconds/86400%60) !== 0) ? ($seconds/86400%60) . 'd' : ''),
-            ($seconds/3600%24),
-            ($seconds/60%60),
-            $seconds%60
+        return $this->duration = trim(
+            sprintf(
+                '%s %02d:%02d:%02d',
+                ((($seconds/86400%60) !== 0) ? ($seconds/86400%60) . 'd' : ''),
+                ($seconds/3600%24),
+                ($seconds/60%60),
+                $seconds%60
+            )
         );
     }
 
diff --git a/tests/AbstractTestCase.php b/tests/AbstractTestCase.php
new file mode 100644
index 0000000..39fcd4a
--- /dev/null
+++ b/tests/AbstractTestCase.php
@@ -0,0 +1,12 @@
+<?php
+
+namespace Symfony\Contracts\Service\Test;
+
+use PHPUnit\Framework\TestCase;
+
+class AbstractTestCase extends TestCase {
+    public function tearDown(): void
+    {
+        rmdir(sys_get_temp_dir() . DIRECTORY_SEPARATOR . 'time-tracking');
+    }
+}
\ No newline at end of file
diff --git a/tests/Service/CommitServiceTest.php b/tests/Service/CommitServiceTest.php
new file mode 100644
index 0000000..d58eb40
--- /dev/null
+++ b/tests/Service/CommitServiceTest.php
@@ -0,0 +1,77 @@
+<?php
+
+namespace Mediashare\TimeTracking\Tests\Service;
+
+use Mediashare\TimeTracking\Collection\CommitCollection;
+use Mediashare\TimeTracking\Collection\StepCollection;
+use Mediashare\TimeTracking\Entity\Commit;
+use Mediashare\TimeTracking\Entity\Step;
+use PHPUnit\Framework\TestCase;
+use Mediashare\TimeTracking\Service\CommitService;
+use Mediashare\TimeTracking\Entity\Config;
+use Mediashare\TimeTracking\Entity\Tracking;
+use Mediashare\TimeTracking\Exception\CommitNotFoundException;
+
+class CommitServiceTest extends TestCase
+{
+    private CommitService $commitService;
+
+    protected function setUp(): void
+    {
+        $config = new Config(
+            trackingDirectory: sys_get_temp_dir() . DIRECTORY_SEPARATOR . 'time-tracking',
+            trackingId: (new \DateTime())->format('YmdHis')
+        );
+
+        $this->commitService = new CommitService($config);
+    }
+
+    public function testCreateCommit(): void {
+        $tracking = $this->commitService->createCommit('Test Commit', '+2 hours');
+
+        $this->assertInstanceOf(Tracking::class, $tracking);
+        $this->assertCount(1, $commits = $tracking->getCommits());
+
+        $this->assertInstanceOf(CommitCollection::class, $commits);
+        $this->assertInstanceOf(Commit::class, $commit = $commits->first());
+
+        $this->assertInstanceOf(StepCollection::class, $steps = $commit->getSteps());
+        $this->assertInstanceOf(Step::class, $lastStep = $steps->first());
+        $this->assertEquals("02:00:00", $lastStep->getDuration());
+
+        $this->assertCount(1, $steps = $tracking->getSteps());
+        $this->assertInstanceOf(StepCollection::class, $steps);
+        $this->assertInstanceOf(Step::class, $steps->first());
+    }
+
+    public function testEditCommit(): void {
+        $tracking = $this->commitService->createCommit('Original Commit', '+1 hour');
+        $originalCommitId = $tracking->getCommits()->first()->getId();
+
+        $tracking = $this->commitService->editCommit($originalCommitId, 'Updated Commit', '+30 minutes');
+
+        $this->assertInstanceOf(Tracking::class, $tracking);
+        $this->assertCount(1, $tracking->getCommits());
+        $this->assertCount(1, $tracking->getSteps());
+
+        $editedCommit = $tracking->getCommits()->first();
+        $this->assertEquals('Updated Commit', $editedCommit->getMessage());
+    }
+
+    public function testRemoveCommit(): void {
+        $tracking = $this->commitService->createCommit('To Be Removed Commit', '+3 hours');
+        $toBeRemovedCommitId = $tracking->getCommits()->first()->getId();
+
+        $tracking = $this->commitService->removeCommit($toBeRemovedCommitId);
+
+        $this->assertInstanceOf(Tracking::class, $tracking);
+        $this->assertCount(0, $tracking->getCommits());
+        $this->assertCount(1, $tracking->getSteps());
+    }
+
+    public function testRemoveNonexistentCommit(): void {
+        $this->expectException(CommitNotFoundException::class);
+
+        $this->commitService->removeCommit('NonexistentCommitId');
+    }
+}
\ No newline at end of file
diff --git a/tests/Service/ConfigServiceTest.php b/tests/Service/ConfigServiceTest.php
new file mode 100644
index 0000000..db9a7e7
--- /dev/null
+++ b/tests/Service/ConfigServiceTest.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Mediashare\TimeTracking\Tests\Service;
+
+use Mediashare\TimeTracking\Entity\Config;
+use Mediashare\TimeTracking\Service\ConfigService;
+use PHPUnit\Framework\TestCase;
+
+class ConfigServiceTest extends TestCase {
+    private ConfigService $configService;
+    private string $tempConfigPath;
+
+    protected function setUp(): void
+    {
+        $this->tempConfigPath = sys_get_temp_dir() . DIRECTORY_SEPARATOR . 'time-tracking' . DIRECTORY_SEPARATOR . 'temp_config.json';
+        $this->configService = new ConfigService();
+    }
+
+    protected function tearDown(): void
+    {
+        if (file_exists($this->tempConfigPath)) {
+            unlink($this->tempConfigPath);
+        }
+    }
+
+    public function testCreateConfig()
+    {
+        $config = $this->configService->createConfig($this->tempConfigPath);
+
+        $this->assertFileExists($this->tempConfigPath);
+        $this->assertInstanceOf(Config::class, $config);
+        $this->assertEquals(Config::DATETIME_FORMAT, $config->getDateTimeFormat());
+    }
+
+    public function testGetLastDateTimeFormat()
+    {
+        // Create a config file with a specific datetime format
+        $config = $this->configService->createConfig($this->tempConfigPath, 'Y-m-d H:i:s');
+        $lastDateTimeFormat = $this->configService->getLastDateTimeFormat();
+
+        $this->assertEquals('Y-m-d H:i:s', $lastDateTimeFormat);
+    }
+
+    public function testGetLastTrackingDirectory()
+    {
+        // Create a config file with a specific tracking directory
+        $config = $this->configService->createConfig($this->tempConfigPath, null, '/path/to/tracking');
+        $lastTrackingDirectory = $this->configService->getLastTrackingDirectory();
+
+        $this->assertEquals('/path/to/tracking', $lastTrackingDirectory);
+    }
+
+    public function testGetLastTrackingId()
+    {
+        // Create a config file with a specific tracking directory and ID
+        $config = $this->configService->createConfig($this->tempConfigPath, null, '/path/to/tracking', '12345');
+        $lastTrackingId = $this->configService->getLastTrackingId('/path/to/tracking');
+
+        $this->assertEquals('12345', $lastTrackingId);
+    }
+}
\ No newline at end of file
diff --git a/tests/Service/StepServiceTest.php b/tests/Service/StepServiceTest.php
new file mode 100644
index 0000000..3d0babb
--- /dev/null
+++ b/tests/Service/StepServiceTest.php
@@ -0,0 +1,65 @@
+<?php
+
+namespace Mediashare\TimeTracking\Tests\Service;
+
+use Mediashare\TimeTracking\Entity\Step;
+use Mediashare\TimeTracking\Service\StepService;
+use PHPUnit\Framework\TestCase;
+
+class StepServiceTest extends TestCase {
+    private StepService $stepService;
+
+    public function setUp(): void {
+        $this->stepService = new StepService();
+    }
+
+
+    public function testCreateStepWithNoDates(): void {
+        $step = $this->stepService->createStep();
+
+        $this->assertInstanceOf(Step::class, $step);
+        $this->assertNotNull($step->getStartDate());
+        $this->assertNull($step->getEndDate());
+    }
+
+    public function testCreateStepWithCustomStartDate(): void {
+        $customStartDate = strtotime('2023-01-01');
+        $step = $this->stepService->createStep($customStartDate);
+
+        $this->assertInstanceOf(Step::class, $step);
+        $this->assertEquals($customStartDate, $step->getStartDate());
+        $this->assertNull($step->getEndDate());
+    }
+
+    public function testCreateStepWithEndDate(): void {
+        $endDate = strtotime('2023-02-01');
+        $step = $this->stepService->createStep(null, $endDate);
+
+        $this->assertInstanceOf(Step::class, $step);
+        $this->assertNotNull($step->getStartDate());
+        $this->assertEquals($endDate, $step->getEndDate());
+    }
+
+    public function testCreateStepWithCustomDuration(): void {
+        $customDuration = '+5 minutes';
+        $step = $this->stepService->createStepWithCustomDuration($customDuration);
+
+        $this->assertInstanceOf(Step::class, $step);
+        $this->assertNotNull($step->getStartDate());
+        $this->assertNotNull($step->getEndDate());
+        $this->assertGreaterThan($step->getStartDate(), $step->getEndDate());
+        $this->assertEquals('00:05:00', $step->getDuration());
+    }
+
+    public function testCreateStepWithCustomDurationAndStartDate(): void {
+        $customDuration = '+2 hours';
+        $customStartDate = strtotime('2023-03-01');
+        $step = $this->stepService->createStepWithCustomDuration($customDuration, $customStartDate);
+
+        $this->assertInstanceOf(Step::class, $step);
+        $this->assertEquals($customStartDate, $step->getStartDate());
+        $this->assertNotNull($step->getEndDate());
+        $this->assertGreaterThan($step->getStartDate(), $step->getEndDate());
+        $this->assertEquals('02:00:00', $step->getDuration());
+    }
+}
\ No newline at end of file
diff --git a/tests/Service/TrackingServiceTest.php b/tests/Service/TrackingServiceTest.php
new file mode 100644
index 0000000..73bc065
--- /dev/null
+++ b/tests/Service/TrackingServiceTest.php
@@ -0,0 +1,86 @@
+<?php
+
+namespace Mediashare\TimeTracking\Tests\Service;
+
+use Mediashare\TimeTracking\Entity\Config;
+use Mediashare\TimeTracking\Entity\Step;
+use Mediashare\TimeTracking\Entity\Tracking;
+use Mediashare\TimeTracking\Exception\TrackingNotFoundException;
+use Mediashare\TimeTracking\Service\TrackingService;
+use PHPUnit\Framework\TestCase;
+
+class TrackingServiceTest extends TestCase {
+    private TrackingService $trackingService;
+    private Config $config;
+
+    protected function setUp(): void
+    {
+        $this->config = new Config(
+            trackingDirectory: sys_get_temp_dir() . DIRECTORY_SEPARATOR . 'time-tracking',
+            trackingId: (new \DateTime())->format('YmdHis')
+        );
+        $this->trackingService = new TrackingService($this->config);
+    }
+
+    public function testCreateTracking(): void {
+        $tracking = $this->trackingService->createTracking(['id' => 'test_id']);
+
+        $this->assertInstanceOf(Tracking::class, $tracking);
+        $this->assertEquals('test_id', $tracking->getId());
+    }
+
+    public function testGetTracking(): void {
+        $tracking = $this->trackingService->getTracking();
+
+        $this->assertInstanceOf(Tracking::class, $tracking);
+        $this->assertTrue($tracking->isRun());
+    }
+
+    public function testStartTracking(): void {
+        $tracking = $this->trackingService->startTracking('Test Tracking', '+1 hour');
+
+        $this->assertTrue($tracking->isRun());
+        $this->assertEquals('Test Tracking', $tracking->getName());
+        $this->assertCount(2, $tracking->getSteps());
+
+        $step = $tracking->getSteps()->first();
+        $this->assertInstanceOf(Step::class, $step);
+        $this->assertTrue($step->getEndDate() > $step->getStartDate());
+
+        $step = $tracking->getSteps()->last();
+        $this->assertInstanceOf(Step::class, $step);
+        $this->assertNotNull($step->getStartDate());
+        $this->assertNull($step->getEndDate());
+    }
+
+    public function testStopTracking(): void {
+        $tracking = $this->trackingService->startTracking('Test Tracking', '+1 hour');
+        $tracking = $this->trackingService->stopTracking();
+
+        $this->assertFalse($tracking->isRun());
+        $this->assertCount(2, $tracking->getSteps());
+
+        $step = $tracking->getSteps()->first();
+        $this->assertInstanceOf(Step::class, $step);
+        $this->assertTrue($step->getEndDate() > $step->getStartDate());
+
+        $step = $tracking->getSteps()->last();
+        $this->assertInstanceOf(Step::class, $step);
+        $this->assertSame($step->getEndDate(), $step->getStartDate());
+    }
+
+    public function testArchiveTracking(): void {
+        $tracking = $this->trackingService->startTracking('Test Tracking', '+1 hour');
+        $tracking = $this->trackingService->archiveTracking();
+
+        $this->assertTrue($tracking->isArchived());
+    }
+
+    public function testRemoveTracking(): void {
+        $tracking = $this->trackingService->startTracking('Test Tracking', '+1 hour');
+        $this->trackingService->removeTracking();
+
+        $this->expectException(TrackingNotFoundException::class);
+        $this->trackingService->getTracking(createItIfNotExist: false);
+    }
+}
\ No newline at end of file
diff --git a/tests/bootstrap.php b/tests/bootstrap.php
new file mode 100644
index 0000000..3181151
--- /dev/null
+++ b/tests/bootstrap.php
@@ -0,0 +1,15 @@
+<?php
+
+use Symfony\Component\Dotenv\Dotenv;
+
+require dirname(__DIR__).'/vendor/autoload.php';
+
+if (file_exists(dirname(__DIR__).'/config/bootstrap.php')) {
+    require dirname(__DIR__).'/config/bootstrap.php';
+} elseif (method_exists(Dotenv::class, 'bootEnv')) {
+    (new Dotenv())->bootEnv(dirname(__DIR__).'/.env');
+}
+
+if ($_SERVER['APP_DEBUG']) {
+    umask(0000);
+}
diff --git a/time-tracking b/time-tracking
index 2f916ca..22c1212 100644
Binary files a/time-tracking and b/time-tracking differ