diff --git a/config/autoload/errorhandler.local.php.dist b/config/autoload/errorhandler.local.php.dist
index d6de56d7..afbc52ed 100644
--- a/config/autoload/errorhandler.local.php.dist
+++ b/config/autoload/errorhandler.local.php.dist
@@ -1,6 +1,5 @@
 <?php
-
-use Shlinkio\Shlink\Common\Expressive\ContentBasedErrorHandler;
+use Shlinkio\Shlink\Common\ErrorHandler\ContentBasedErrorHandler;
 use Zend\Expressive\Container\WhoopsErrorHandlerFactory;
 
 return [
diff --git a/config/autoload/services.global.php b/config/autoload/services.global.php
index 841a389a..44bbbbdd 100644
--- a/config/autoload/services.global.php
+++ b/config/autoload/services.global.php
@@ -1,8 +1,5 @@
 <?php
-use Acelaya\ZsmAnnotatedServices\Factory\V3\AnnotatedFactory;
-use Shlinkio\Shlink\Common\Expressive\ContentBasedErrorHandler;
-use Shlinkio\Shlink\Common\Expressive\ErrorHandlerManager;
-use Shlinkio\Shlink\Common\Expressive\ErrorHandlerManagerFactory;
+use Shlinkio\Shlink\Common\ErrorHandler\ContentBasedErrorHandler;
 use Zend\Expressive;
 use Zend\Expressive\Container;
 use Zend\Expressive\Helper;
@@ -25,8 +22,6 @@ return [
             Router\FastRouteRouter::class => InvokableFactory::class,
 
             // View
-            ContentBasedErrorHandler::class => AnnotatedFactory::class,
-            ErrorHandlerManager::class => ErrorHandlerManagerFactory::class,
             Template\TemplateRendererInterface::class => Twig\TwigRendererFactory::class,
         ],
         'aliases' => [
diff --git a/module/CLI/src/Command/GenerateShortcodeCommand.php b/module/CLI/src/Command/GenerateShortcodeCommand.php
index 0a0af9eb..f02c110b 100644
--- a/module/CLI/src/Command/GenerateShortcodeCommand.php
+++ b/module/CLI/src/Command/GenerateShortcodeCommand.php
@@ -52,7 +52,7 @@ class GenerateShortcodeCommand extends Command
     {
         $this->setName('shortcode:generate')
              ->setDescription(
-                 $this->translator->translate('Generates a shortcode for provided URL and returns the short URL')
+                 $this->translator->translate('Generates a short code for provided URL and returns the short URL')
              )
              ->addArgument('longUrl', InputArgument::REQUIRED, $this->translator->translate('The long URL to parse'));
     }
@@ -87,8 +87,8 @@ class GenerateShortcodeCommand extends Command
                 return;
             }
 
-            $shortcode = $this->urlShortener->urlToShortCode(new Uri($longUrl));
-            $shortUrl = (new Uri())->withPath($shortcode)
+            $shortCode = $this->urlShortener->urlToShortCode(new Uri($longUrl));
+            $shortUrl = (new Uri())->withPath($shortCode)
                 ->withScheme($this->domainConfig['schema'])
                 ->withHost($this->domainConfig['hostname']);
 
diff --git a/module/CLI/src/Factory/ApplicationFactory.php b/module/CLI/src/Factory/ApplicationFactory.php
index 51d5fdb3..a8e24bf3 100644
--- a/module/CLI/src/Factory/ApplicationFactory.php
+++ b/module/CLI/src/Factory/ApplicationFactory.php
@@ -25,7 +25,7 @@ class ApplicationFactory implements FactoryInterface
     public function __invoke(ContainerInterface $container, $requestedName, array $options = null)
     {
         $config = $container->get('config')['cli'];
-        $app = new CliApp();
+        $app = new CliApp('Shlink', '1.0.0');
 
         $commands = isset($config['commands']) ? $config['commands'] : [];
         foreach ($commands as $command) {
diff --git a/module/CLI/test/Command/GenerateShortcodeCommandTest.php b/module/CLI/test/Command/GenerateShortcodeCommandTest.php
new file mode 100644
index 00000000..45cb8130
--- /dev/null
+++ b/module/CLI/test/Command/GenerateShortcodeCommandTest.php
@@ -0,0 +1,70 @@
+<?php
+namespace ShlinkioTest\Shlink\CLI\Command;
+
+use PHPUnit_Framework_TestCase as TestCase;
+use Prophecy\Argument;
+use Prophecy\Prophecy\ObjectProphecy;
+use Shlinkio\Shlink\CLI\Command\GenerateShortcodeCommand;
+use Shlinkio\Shlink\Core\Exception\InvalidUrlException;
+use Shlinkio\Shlink\Core\Service\UrlShortener;
+use Symfony\Component\Console\Application;
+use Symfony\Component\Console\Tester\CommandTester;
+use Zend\I18n\Translator\Translator;
+
+class GenerateShortcodeCommandTest extends TestCase
+{
+    /**
+     * @var CommandTester
+     */
+    protected $commandTester;
+    /**
+     * @var ObjectProphecy
+     */
+    protected $urlShortener;
+
+    public function setUp()
+    {
+        $this->urlShortener = $this->prophesize(UrlShortener::class);
+        $command = new GenerateShortcodeCommand($this->urlShortener->reveal(), Translator::factory([]), [
+            'schema' => 'http',
+            'hostname' => 'foo.com'
+        ]);
+        $app = new Application();
+        $app->add($command);
+        $this->commandTester = new CommandTester($command);
+    }
+
+    /**
+     * @test
+     */
+    public function properShortCodeIsCreatedIfLongUrlIsCorrect()
+    {
+        $this->urlShortener->urlToShortCode(Argument::any())->willReturn('abc123')
+                                                            ->shouldBeCalledTimes(1);
+
+        $this->commandTester->execute([
+            'command' => 'shortcode:generate',
+            'longUrl' => 'http://domain.com/foo/bar'
+        ]);
+        $output = $this->commandTester->getDisplay();
+        $this->assertTrue(strpos($output, 'http://foo.com/abc123') > 0);
+    }
+
+    /**
+     * @test
+     */
+    public function exceptionWhileParsingLongUrlOutputsError()
+    {
+        $this->urlShortener->urlToShortCode(Argument::any())->willThrow(new InvalidUrlException())
+                                                            ->shouldBeCalledTimes(1);
+
+        $this->commandTester->execute([
+            'command' => 'shortcode:generate',
+            'longUrl' => 'http://domain.com/invalid'
+        ]);
+        $output = $this->commandTester->getDisplay();
+        $this->assertTrue(
+            strpos($output, 'Provided URL "http://domain.com/invalid" is invalid. Try with a different one.') === 0
+        );
+    }
+}
diff --git a/module/CLI/test/Command/GetVisitsCommandTest.php b/module/CLI/test/Command/GetVisitsCommandTest.php
new file mode 100644
index 00000000..4294823b
--- /dev/null
+++ b/module/CLI/test/Command/GetVisitsCommandTest.php
@@ -0,0 +1,91 @@
+<?php
+namespace ShlinkioTest\Shlink\CLI\Command;
+
+use PHPUnit_Framework_TestCase as TestCase;
+use Prophecy\Argument;
+use Prophecy\Prophecy\ObjectProphecy;
+use Shlinkio\Shlink\CLI\Command\GetVisitsCommand;
+use Shlinkio\Shlink\Common\Util\DateRange;
+use Shlinkio\Shlink\Core\Entity\Visit;
+use Shlinkio\Shlink\Core\Service\VisitsTrackerInterface;
+use Symfony\Component\Console\Application;
+use Symfony\Component\Console\Tester\CommandTester;
+use Zend\I18n\Translator\Translator;
+
+class GetVisitsCommandTest extends TestCase
+{
+    /**
+     * @var CommandTester
+     */
+    protected $commandTester;
+    /**
+     * @var ObjectProphecy
+     */
+    protected $visitsTracker;
+
+    public function setUp()
+    {
+        $this->visitsTracker = $this->prophesize(VisitsTrackerInterface::class);
+        $command = new GetVisitsCommand($this->visitsTracker->reveal(), Translator::factory([]));
+        $app = new Application();
+        $app->add($command);
+        $this->commandTester = new CommandTester($command);
+    }
+
+    /**
+     * @test
+     */
+    public function noDateFlagsTriesToListWithoutDateRange()
+    {
+        $shortCode = 'abc123';
+        $this->visitsTracker->info($shortCode, new DateRange(null, null))->willReturn([])
+                                                                         ->shouldBeCalledTimes(1);
+
+        $this->commandTester->execute([
+            'command' => 'shortcode:visits',
+            'shortCode' => $shortCode,
+        ]);
+    }
+
+    /**
+     * @test
+     */
+    public function providingDateFlagsTheListGetsFiltered()
+    {
+        $shortCode = 'abc123';
+        $startDate = '2016-01-01';
+        $endDate = '2016-02-01';
+        $this->visitsTracker->info($shortCode, new DateRange(new \DateTime($startDate), new \DateTime($endDate)))
+            ->willReturn([])
+            ->shouldBeCalledTimes(1);
+
+        $this->commandTester->execute([
+            'command' => 'shortcode:visits',
+            'shortCode' => $shortCode,
+            '--startDate' => $startDate,
+            '--endDate' => $endDate,
+        ]);
+    }
+
+    /**
+     * @test
+     */
+    public function outputIsProperlyGenerated()
+    {
+        $shortCode = 'abc123';
+        $this->visitsTracker->info($shortCode, Argument::any())->willReturn([
+            (new Visit())->setReferer('foo')
+                         ->setRemoteAddr('1.2.3.4')
+                         ->setUserAgent('bar'),
+        ])->shouldBeCalledTimes(1);
+
+        $this->commandTester->execute([
+            'command' => 'shortcode:visits',
+            'shortCode' => $shortCode,
+        ]);
+        $output = $this->commandTester->getDisplay();
+        $this->assertTrue(strpos($output, 'foo') > 0);
+        $this->assertTrue(strpos($output, '1.2.3.4') > 0);
+        $this->assertTrue(strpos($output, 'bar') > 0);
+    }
+}
diff --git a/module/CLI/test/Command/ProcessVisitsCommandTest.php b/module/CLI/test/Command/ProcessVisitsCommandTest.php
new file mode 100644
index 00000000..23463123
--- /dev/null
+++ b/module/CLI/test/Command/ProcessVisitsCommandTest.php
@@ -0,0 +1,96 @@
+<?php
+namespace ShlinkioTest\Shlink\CLI\Command;
+
+use PHPUnit_Framework_TestCase as TestCase;
+use Prophecy\Argument;
+use Prophecy\Prophecy\ObjectProphecy;
+use Shlinkio\Shlink\CLI\Command\ProcessVisitsCommand;
+use Shlinkio\Shlink\Common\Service\IpLocationResolver;
+use Shlinkio\Shlink\Core\Entity\Visit;
+use Shlinkio\Shlink\Core\Service\VisitService;
+use Symfony\Component\Console\Application;
+use Symfony\Component\Console\Tester\CommandTester;
+use Zend\I18n\Translator\Translator;
+
+class ProcessVisitsCommandTest extends TestCase
+{
+    /**
+     * @var CommandTester
+     */
+    protected $commandTester;
+    /**
+     * @var ObjectProphecy
+     */
+    protected $visitService;
+    /**
+     * @var ObjectProphecy
+     */
+    protected $ipResolver;
+
+    public function setUp()
+    {
+        $this->visitService = $this->prophesize(VisitService::class);
+        $this->ipResolver = $this->prophesize(IpLocationResolver::class);
+        $command = new ProcessVisitsCommand(
+            $this->visitService->reveal(),
+            $this->ipResolver->reveal(),
+            Translator::factory([])
+        );
+        $app = new Application();
+        $app->add($command);
+
+        $this->commandTester = new CommandTester($command);
+    }
+
+    /**
+     * @test
+     */
+    public function allReturnedVisitsIpsAreProcessed()
+    {
+        $visits = [
+            (new Visit())->setRemoteAddr('1.2.3.4'),
+            (new Visit())->setRemoteAddr('4.3.2.1'),
+            (new Visit())->setRemoteAddr('12.34.56.78'),
+        ];
+        $this->visitService->getUnlocatedVisits()->willReturn($visits)
+                                                 ->shouldBeCalledTimes(1);
+
+        $this->visitService->saveVisit(Argument::any())->shouldBeCalledTimes(count($visits));
+        $this->ipResolver->resolveIpLocation(Argument::any())->willReturn([])
+                                                             ->shouldBeCalledTimes(count($visits));
+
+        $this->commandTester->execute([
+            'command' => 'visit:process',
+        ]);
+        $output = $this->commandTester->getDisplay();
+        $this->assertTrue(strpos($output, 'Processing IP 1.2.3.4') === 0);
+        $this->assertTrue(strpos($output, 'Processing IP 4.3.2.1') > 0);
+        $this->assertTrue(strpos($output, 'Processing IP 12.34.56.78') > 0);
+    }
+
+    /**
+     * @test
+     */
+    public function localhostAddressIsIgnored()
+    {
+        $visits = [
+            (new Visit())->setRemoteAddr('1.2.3.4'),
+            (new Visit())->setRemoteAddr('4.3.2.1'),
+            (new Visit())->setRemoteAddr('12.34.56.78'),
+            (new Visit())->setRemoteAddr('127.0.0.1'),
+            (new Visit())->setRemoteAddr('127.0.0.1'),
+        ];
+        $this->visitService->getUnlocatedVisits()->willReturn($visits)
+            ->shouldBeCalledTimes(1);
+
+        $this->visitService->saveVisit(Argument::any())->shouldBeCalledTimes(count($visits) - 2);
+        $this->ipResolver->resolveIpLocation(Argument::any())->willReturn([])
+                                                             ->shouldBeCalledTimes(count($visits) - 2);
+
+        $this->commandTester->execute([
+            'command' => 'visit:process',
+        ]);
+        $output = $this->commandTester->getDisplay();
+        $this->assertTrue(strpos($output, 'Ignored localhost address') > 0);
+    }
+}
diff --git a/module/CLI/test/Command/ResolveUrlCommandTest.php b/module/CLI/test/Command/ResolveUrlCommandTest.php
new file mode 100644
index 00000000..a2f47c92
--- /dev/null
+++ b/module/CLI/test/Command/ResolveUrlCommandTest.php
@@ -0,0 +1,85 @@
+<?php
+namespace ShlinkioTest\Shlink\CLI\Command;
+
+use PHPUnit_Framework_TestCase as TestCase;
+use Prophecy\Prophecy\ObjectProphecy;
+use Shlinkio\Shlink\CLI\Command\ResolveUrlCommand;
+use Shlinkio\Shlink\Core\Exception\InvalidShortCodeException;
+use Shlinkio\Shlink\Core\Service\UrlShortener;
+use Symfony\Component\Console\Application;
+use Symfony\Component\Console\Tester\CommandTester;
+use Zend\I18n\Translator\Translator;
+
+class ResolveUrlCommandTest extends TestCase
+{
+    /**
+     * @var CommandTester
+     */
+    protected $commandTester;
+    /**
+     * @var ObjectProphecy
+     */
+    protected $urlShortener;
+
+    public function setUp()
+    {
+        $this->urlShortener = $this->prophesize(UrlShortener::class);
+        $command = new ResolveUrlCommand($this->urlShortener->reveal(), Translator::factory([]));
+        $app = new Application();
+        $app->add($command);
+
+        $this->commandTester = new CommandTester($command);
+    }
+
+    /**
+     * @test
+     */
+    public function correctShortCodeResolvesUrl()
+    {
+        $shortCode = 'abc123';
+        $expectedUrl = 'http://domain.com/foo/bar';
+        $this->urlShortener->shortCodeToUrl($shortCode)->willReturn($expectedUrl)
+                                                       ->shouldBeCalledTimes(1);
+
+        $this->commandTester->execute([
+            'command' => 'shortcode:parse',
+            'shortCode' => $shortCode,
+        ]);
+        $output = $this->commandTester->getDisplay();
+        $this->assertEquals('Long URL: ' . $expectedUrl . PHP_EOL, $output);
+    }
+
+    /**
+     * @test
+     */
+    public function incorrectShortCodeOutputsErrorMessage()
+    {
+        $shortCode = 'abc123';
+        $this->urlShortener->shortCodeToUrl($shortCode)->willReturn(null)
+                                                       ->shouldBeCalledTimes(1);
+
+        $this->commandTester->execute([
+            'command' => 'shortcode:parse',
+            'shortCode' => $shortCode,
+        ]);
+        $output = $this->commandTester->getDisplay();
+        $this->assertEquals('No URL found for short code "' . $shortCode . '"' . PHP_EOL, $output);
+    }
+
+    /**
+     * @test
+     */
+    public function wrongShortCodeFormatOutputsErrorMessage()
+    {
+        $shortCode = 'abc123';
+        $this->urlShortener->shortCodeToUrl($shortCode)->willThrow(new InvalidShortCodeException())
+                                                       ->shouldBeCalledTimes(1);
+
+        $this->commandTester->execute([
+            'command' => 'shortcode:parse',
+            'shortCode' => $shortCode,
+        ]);
+        $output = $this->commandTester->getDisplay();
+        $this->assertEquals('Provided short code "' . $shortCode . '" has an invalid format.' . PHP_EOL, $output);
+    }
+}
diff --git a/module/Common/config/error-handler.config.php b/module/Common/config/error-handler.config.php
index a6165fa2..d19b9ac6 100644
--- a/module/Common/config/error-handler.config.php
+++ b/module/Common/config/error-handler.config.php
@@ -1,5 +1,5 @@
 <?php
-use Shlinkio\Shlink\Common\Expressive\ContentBasedErrorHandler;
+use Shlinkio\Shlink\Common\ErrorHandler\ContentBasedErrorHandler;
 use Zend\Expressive\Container\TemplatedErrorHandlerFactory;
 use Zend\Stratigility\FinalHandler;
 
diff --git a/module/Common/config/services.config.php b/module/Common/config/services.config.php
index 42d9dbc5..be062b86 100644
--- a/module/Common/config/services.config.php
+++ b/module/Common/config/services.config.php
@@ -2,6 +2,7 @@
 use Acelaya\ZsmAnnotatedServices\Factory\V3\AnnotatedFactory;
 use Doctrine\Common\Cache\Cache;
 use Doctrine\ORM\EntityManager;
+use Shlinkio\Shlink\Common\ErrorHandler;
 use Shlinkio\Shlink\Common\Factory\CacheFactory;
 use Shlinkio\Shlink\Common\Factory\EntityManagerFactory;
 use Shlinkio\Shlink\Common\Factory\TranslatorFactory;
@@ -22,6 +23,9 @@ return [
             Translator::class => TranslatorFactory::class,
             TranslatorExtension::class => AnnotatedFactory::class,
             LocaleMiddleware::class => AnnotatedFactory::class,
+
+            ErrorHandler\ContentBasedErrorHandler::class => AnnotatedFactory::class,
+            ErrorHandler\ErrorHandlerManager::class => ErrorHandler\ErrorHandlerManagerFactory::class,
         ],
         'aliases' => [
             'em' => EntityManager::class,
diff --git a/module/Common/src/Expressive/ContentBasedErrorHandler.php b/module/Common/src/ErrorHandler/ContentBasedErrorHandler.php
similarity index 73%
rename from module/Common/src/Expressive/ContentBasedErrorHandler.php
rename to module/Common/src/ErrorHandler/ContentBasedErrorHandler.php
index df6cde91..be19e848 100644
--- a/module/Common/src/Expressive/ContentBasedErrorHandler.php
+++ b/module/Common/src/ErrorHandler/ContentBasedErrorHandler.php
@@ -1,5 +1,5 @@
 <?php
-namespace Shlinkio\Shlink\Common\Expressive;
+namespace Shlinkio\Shlink\Common\ErrorHandler;
 
 use Acelaya\ZsmAnnotatedServices\Annotation\Inject;
 use Psr\Http\Message\ResponseInterface as Response;
@@ -49,6 +49,7 @@ class ContentBasedErrorHandler implements ErrorHandlerInterface
      */
     protected function resolveErrorHandlerFromAcceptHeader(Request $request)
     {
+        // Try to find an error handler for one of the accepted content types
         $accepts = $request->hasHeader('Accept') ? $request->getHeaderLine('Accept') : self::DEFAULT_CONTENT;
         $accepts = explode(',', $accepts);
         foreach ($accepts as $accept) {
@@ -59,8 +60,17 @@ class ContentBasedErrorHandler implements ErrorHandlerInterface
             return $this->errorHandlerManager->get($accept);
         }
 
+        // If it wasn't possible to find an error handler for accepted content type, use default one if registered
+        if ($this->errorHandlerManager->has(self::DEFAULT_CONTENT)) {
+            return $this->errorHandlerManager->get(self::DEFAULT_CONTENT);
+        }
+
+        // It wasn't possible to find an error handler
         throw new InvalidArgumentException(sprintf(
-            'It wasn\'t possible to find an error handler for '
+            'It wasn\'t possible to find an error handler for ["%s"] content types. '
+            . 'Make sure you have registered at least the default "%s" content type',
+            implode('", "', $accepts),
+            self::DEFAULT_CONTENT
         ));
     }
 }
diff --git a/module/Common/src/Expressive/ErrorHandlerInterface.php b/module/Common/src/ErrorHandler/ErrorHandlerInterface.php
similarity index 89%
rename from module/Common/src/Expressive/ErrorHandlerInterface.php
rename to module/Common/src/ErrorHandler/ErrorHandlerInterface.php
index 9f0b5803..9676c40a 100644
--- a/module/Common/src/Expressive/ErrorHandlerInterface.php
+++ b/module/Common/src/ErrorHandler/ErrorHandlerInterface.php
@@ -1,5 +1,5 @@
 <?php
-namespace Shlinkio\Shlink\Common\Expressive;
+namespace Shlinkio\Shlink\Common\ErrorHandler;
 
 use Psr\Http\Message\ServerRequestInterface as Request;
 use Psr\Http\Message\ResponseInterface as Response;
diff --git a/module/Common/src/Expressive/ErrorHandlerManager.php b/module/Common/src/ErrorHandler/ErrorHandlerManager.php
similarity index 92%
rename from module/Common/src/Expressive/ErrorHandlerManager.php
rename to module/Common/src/ErrorHandler/ErrorHandlerManager.php
index 5cce0095..1bc66476 100644
--- a/module/Common/src/Expressive/ErrorHandlerManager.php
+++ b/module/Common/src/ErrorHandler/ErrorHandlerManager.php
@@ -1,5 +1,5 @@
 <?php
-namespace Shlinkio\Shlink\Common\Expressive;
+namespace Shlinkio\Shlink\Common\ErrorHandler;
 
 use Zend\ServiceManager\AbstractPluginManager;
 use Zend\ServiceManager\Exception\InvalidServiceException;
diff --git a/module/Common/src/Expressive/ErrorHandlerManagerFactory.php b/module/Common/src/ErrorHandler/ErrorHandlerManagerFactory.php
similarity index 95%
rename from module/Common/src/Expressive/ErrorHandlerManagerFactory.php
rename to module/Common/src/ErrorHandler/ErrorHandlerManagerFactory.php
index e96e1ca3..08a1fd83 100644
--- a/module/Common/src/Expressive/ErrorHandlerManagerFactory.php
+++ b/module/Common/src/ErrorHandler/ErrorHandlerManagerFactory.php
@@ -1,5 +1,5 @@
 <?php
-namespace Shlinkio\Shlink\Common\Expressive;
+namespace Shlinkio\Shlink\Common\ErrorHandler;
 
 use Interop\Container\ContainerInterface;
 use Interop\Container\Exception\ContainerException;
diff --git a/module/Common/src/Expressive/ErrorHandlerManagerInterface.php b/module/Common/src/ErrorHandler/ErrorHandlerManagerInterface.php
similarity index 72%
rename from module/Common/src/Expressive/ErrorHandlerManagerInterface.php
rename to module/Common/src/ErrorHandler/ErrorHandlerManagerInterface.php
index 371cbbf4..323bfe4b 100644
--- a/module/Common/src/Expressive/ErrorHandlerManagerInterface.php
+++ b/module/Common/src/ErrorHandler/ErrorHandlerManagerInterface.php
@@ -1,5 +1,5 @@
 <?php
-namespace Shlinkio\Shlink\Common\Expressive;
+namespace Shlinkio\Shlink\Common\ErrorHandler;
 
 use Interop\Container\ContainerInterface;
 
diff --git a/module/Common/test/ConfigProviderTest.php b/module/Common/test/ConfigProviderTest.php
new file mode 100644
index 00000000..54c8c65f
--- /dev/null
+++ b/module/Common/test/ConfigProviderTest.php
@@ -0,0 +1,31 @@
+<?php
+namespace ShlinkioTest\Shlink\Common;
+
+use PHPUnit_Framework_TestCase as TestCase;
+use Shlinkio\Shlink\Common\ConfigProvider;
+
+class ConfigProviderTest extends TestCase
+{
+    /**
+     * @var ConfigProvider
+     */
+    protected $configProvider;
+
+    public function setUp()
+    {
+        $this->configProvider = new ConfigProvider();
+    }
+
+    /**
+     * @test
+     */
+    public function configIsReturned()
+    {
+        $config = $this->configProvider->__invoke();
+
+        $this->assertArrayHasKey('error_handler', $config);
+        $this->assertArrayHasKey('middleware_pipeline', $config);
+        $this->assertArrayHasKey('services', $config);
+        $this->assertArrayHasKey('twig', $config);
+    }
+}
diff --git a/module/Common/test/ErrorHandler/ContentBasedErrorHandlerTest.php b/module/Common/test/ErrorHandler/ContentBasedErrorHandlerTest.php
new file mode 100644
index 00000000..6b480e54
--- /dev/null
+++ b/module/Common/test/ErrorHandler/ContentBasedErrorHandlerTest.php
@@ -0,0 +1,75 @@
+<?php
+namespace ShlinkioTest\Shlink\Common\ErrorHandler;
+
+use PHPUnit_Framework_TestCase as TestCase;
+use Shlinkio\Shlink\Common\ErrorHandler\ContentBasedErrorHandler;
+use Shlinkio\Shlink\Common\ErrorHandler\ErrorHandlerManager;
+use Zend\Diactoros\Response;
+use Zend\Diactoros\ServerRequestFactory;
+use Zend\ServiceManager\ServiceManager;
+
+class ContentBasedErrorHandlerTest extends TestCase
+{
+    /**
+     * @var ContentBasedErrorHandler
+     */
+    protected $errorHandler;
+
+    public function setUp()
+    {
+        $this->errorHandler = new ContentBasedErrorHandler(new ErrorHandlerManager(new ServiceManager(), [
+            'factories' => [
+                'text/html' => [$this, 'factory'],
+                'application/json' => [$this, 'factory'],
+            ],
+        ]));
+    }
+
+    public function factory($container, $name)
+    {
+        return function () use ($name) {
+            return $name;
+        };
+    }
+
+    /**
+     * @test
+     */
+    public function correctAcceptHeaderValueInvokesErrorHandler()
+    {
+        $request = ServerRequestFactory::fromGlobals()->withHeader('Accept', 'foo/bar,application/json');
+        $result = $this->errorHandler->__invoke($request, new Response());
+        $this->assertEquals('application/json', $result);
+    }
+
+    /**
+     * @test
+     */
+    public function defaultContentTypeIsUsedWhenNoAcceptHeaderisPresent()
+    {
+        $request = ServerRequestFactory::fromGlobals();
+        $result = $this->errorHandler->__invoke($request, new Response());
+        $this->assertEquals('text/html', $result);
+    }
+
+    /**
+     * @test
+     */
+    public function defaultContentTypeIsUsedWhenAcceptedContentIsNotSupported()
+    {
+        $request = ServerRequestFactory::fromGlobals()->withHeader('Accept', 'foo/bar,text/xml');
+        $result = $this->errorHandler->__invoke($request, new Response());
+        $this->assertEquals('text/html', $result);
+    }
+
+    /**
+     * @test
+     * @expectedException \Shlinkio\Shlink\Common\Exception\InvalidArgumentException
+     */
+    public function ifNoErrorHandlerIsFoundAnExceptionIsThrown()
+    {
+        $this->errorHandler = new ContentBasedErrorHandler(new ErrorHandlerManager(new ServiceManager(), []));
+        $request = ServerRequestFactory::fromGlobals()->withHeader('Accept', 'foo/bar,text/xml');
+        $result = $this->errorHandler->__invoke($request, new Response());
+    }
+}
diff --git a/module/Common/test/ErrorHandler/ErrorHandlerManagerFactoryTest.php b/module/Common/test/ErrorHandler/ErrorHandlerManagerFactoryTest.php
new file mode 100644
index 00000000..be6d4e6d
--- /dev/null
+++ b/module/Common/test/ErrorHandler/ErrorHandlerManagerFactoryTest.php
@@ -0,0 +1,35 @@
+<?php
+namespace ShlinkioTest\Shlink\Common\ErrorHandler;
+
+use PHPUnit_Framework_TestCase as TestCase;
+use Shlinkio\Shlink\Common\ErrorHandler\ErrorHandlerManager;
+use Shlinkio\Shlink\Common\ErrorHandler\ErrorHandlerManagerFactory;
+use Zend\ServiceManager\ServiceManager;
+
+class ErrorHandlerManagerFactoryTest extends TestCase
+{
+    /**
+     * @var ErrorHandlerManagerFactory
+     */
+    protected $factory;
+
+    public function setUp()
+    {
+        $this->factory = new ErrorHandlerManagerFactory();
+    }
+
+    /**
+     * @test
+     */
+    public function serviceIsCreated()
+    {
+        $instance = $this->factory->__invoke(new ServiceManager(['services' => [
+            'config' => [
+                'error_handler' => [
+                    'plugins' => [],
+                ],
+            ],
+        ]]), '');
+        $this->assertInstanceOf(ErrorHandlerManager::class, $instance);
+    }
+}
diff --git a/module/Common/test/ErrorHandler/ErrorHandlerManagerTest.php b/module/Common/test/ErrorHandler/ErrorHandlerManagerTest.php
new file mode 100644
index 00000000..4b14f113
--- /dev/null
+++ b/module/Common/test/ErrorHandler/ErrorHandlerManagerTest.php
@@ -0,0 +1,45 @@
+<?php
+namespace ShlinkioTest\Shlink\Common\ErrorHandler;
+
+use PHPUnit_Framework_TestCase as TestCase;
+use Shlinkio\Shlink\Common\ErrorHandler\ErrorHandlerManager;
+use Zend\ServiceManager\ServiceManager;
+
+class ErrorHandlerManagerTest extends TestCase
+{
+    /**
+     * @var ErrorHandlerManager
+     */
+    protected $pluginManager;
+
+    public function setUp()
+    {
+        $this->pluginManager = new ErrorHandlerManager(new ServiceManager(), [
+            'services' => [
+                'foo' => function () {
+                },
+            ],
+            'invokables' => [
+                'invalid' => \stdClass::class,
+            ]
+        ]);
+    }
+
+    /**
+     * @test
+     */
+    public function callablesAreReturned()
+    {
+        $instance = $this->pluginManager->get('foo');
+        $this->assertInstanceOf(\Closure::class, $instance);
+    }
+
+    /**
+     * @test
+     * @expectedException \Zend\ServiceManager\Exception\InvalidServiceException
+     */
+    public function nonCallablesThrowException()
+    {
+        $this->pluginManager->get('invalid');
+    }
+}
diff --git a/module/Common/test/Factory/TranslatorFactoryTest.php b/module/Common/test/Factory/TranslatorFactoryTest.php
new file mode 100644
index 00000000..e70f820b
--- /dev/null
+++ b/module/Common/test/Factory/TranslatorFactoryTest.php
@@ -0,0 +1,31 @@
+<?php
+namespace ShlinkioTest\Shlink\Common\Factory;
+
+use PHPUnit_Framework_TestCase as TestCase;
+use Shlinkio\Shlink\Common\Factory\TranslatorFactory;
+use Zend\I18n\Translator\Translator;
+use Zend\ServiceManager\ServiceManager;
+
+class TranslatorFactoryTest extends TestCase
+{
+    /**
+     * @var TranslatorFactory
+     */
+    protected $factory;
+
+    public function setUp()
+    {
+        $this->factory = new TranslatorFactory();
+    }
+
+    /**
+     * @test
+     */
+    public function serviceIsCreated()
+    {
+        $instance = $this->factory->__invoke(new ServiceManager(['services' => [
+            'config' => [],
+        ]]), '');
+        $this->assertInstanceOf(Translator::class, $instance);
+    }
+}
diff --git a/module/Common/test/Middleware/LocaleMiddlewareTest.php b/module/Common/test/Middleware/LocaleMiddlewareTest.php
new file mode 100644
index 00000000..72e6bf77
--- /dev/null
+++ b/module/Common/test/Middleware/LocaleMiddlewareTest.php
@@ -0,0 +1,71 @@
+<?php
+namespace ShlinkioTest\Shlink\Common\Middleware;
+
+use PHPUnit_Framework_TestCase as TestCase;
+use Shlinkio\Shlink\Common\Middleware\LocaleMiddleware;
+use Zend\Diactoros\Response;
+use Zend\Diactoros\ServerRequestFactory;
+use Zend\I18n\Translator\Translator;
+
+class LocaleMiddlewareTest extends TestCase
+{
+    /**
+     * @var LocaleMiddleware
+     */
+    protected $middleware;
+    /**
+     * @var Translator
+     */
+    protected $translator;
+
+    public function setUp()
+    {
+        $this->translator = Translator::factory(['locale' => 'ru']);
+        $this->middleware = new LocaleMiddleware($this->translator);
+    }
+
+    /**
+     * @test
+     */
+    public function whenNoHeaderIsPresentLocaleIsNotChanged()
+    {
+        $this->assertEquals('ru', $this->translator->getLocale());
+        $this->middleware->__invoke(ServerRequestFactory::fromGlobals(), new Response(), function ($req, $resp) {
+            return $resp;
+        });
+        $this->assertEquals('ru', $this->translator->getLocale());
+    }
+
+    /**
+     * @test
+     */
+    public function whenTheHeaderIsPresentLocaleIsChanged()
+    {
+        $this->assertEquals('ru', $this->translator->getLocale());
+        $request = ServerRequestFactory::fromGlobals()->withHeader('Accept-Language', 'es');
+        $this->middleware->__invoke($request, new Response(), function ($req, $resp) {
+            return $resp;
+        });
+        $this->assertEquals('es', $this->translator->getLocale());
+    }
+
+    /**
+     * @test
+     */
+    public function localeGetsNormalized()
+    {
+        $this->assertEquals('ru', $this->translator->getLocale());
+
+        $request = ServerRequestFactory::fromGlobals()->withHeader('Accept-Language', 'es_ES');
+        $this->middleware->__invoke($request, new Response(), function ($req, $resp) {
+            return $resp;
+        });
+        $this->assertEquals('es', $this->translator->getLocale());
+
+        $request = ServerRequestFactory::fromGlobals()->withHeader('Accept-Language', 'en-US');
+        $this->middleware->__invoke($request, new Response(), function ($req, $resp) {
+            return $resp;
+        });
+        $this->assertEquals('en', $this->translator->getLocale());
+    }
+}
diff --git a/module/Common/test/Paginator/PaginableRepositoryAdapterTest.php b/module/Common/test/Paginator/PaginableRepositoryAdapterTest.php
new file mode 100644
index 00000000..1135682f
--- /dev/null
+++ b/module/Common/test/Paginator/PaginableRepositoryAdapterTest.php
@@ -0,0 +1,43 @@
+<?php
+namespace ShlinkioTest\Shlink\Common\Paginator;
+
+use PHPUnit_Framework_TestCase as TestCase;
+use Prophecy\Prophecy\ObjectProphecy;
+use Shlinkio\Shlink\Common\Paginator\Adapter\PaginableRepositoryAdapter;
+use Shlinkio\Shlink\Common\Repository\PaginableRepositoryInterface;
+
+class PaginableRepositoryAdapterTest extends TestCase
+{
+    /**
+     * @var PaginableRepositoryAdapter
+     */
+    protected $adapter;
+    /**
+     * @var ObjectProphecy
+     */
+    protected $repo;
+
+    public function setUp()
+    {
+        $this->repo = $this->prophesize(PaginableRepositoryInterface::class);
+        $this->adapter = new PaginableRepositoryAdapter($this->repo->reveal(), 'search', 'order');
+    }
+
+    /**
+     * @test
+     */
+    public function getItemsFallbacksToFindList()
+    {
+        $this->repo->findList(10, 5, 'search', 'order')->shouldBeCalledTimes(1);
+        $this->adapter->getItems(5, 10);
+    }
+
+    /**
+     * @test
+     */
+    public function countFallbacksToCountList()
+    {
+        $this->repo->countList('search')->shouldBeCalledTimes(1);
+        $this->adapter->count();
+    }
+}
diff --git a/module/Common/test/Service/IpLocationResolverTest.php b/module/Common/test/Service/IpLocationResolverTest.php
new file mode 100644
index 00000000..e6130569
--- /dev/null
+++ b/module/Common/test/Service/IpLocationResolverTest.php
@@ -0,0 +1,56 @@
+<?php
+namespace ShlinkioTest\Shlink\Common\Service;
+
+use GuzzleHttp\Client;
+use GuzzleHttp\Exception\TransferException;
+use GuzzleHttp\Psr7\Response;
+use PHPUnit_Framework_TestCase as TestCase;
+use Prophecy\Prophecy\ObjectProphecy;
+use Shlinkio\Shlink\Common\Service\IpLocationResolver;
+
+class IpLocationResolverTest extends TestCase
+{
+    /**
+     * @var IpLocationResolver
+     */
+    protected $ipResolver;
+    /**
+     * @var ObjectProphecy
+     */
+    protected $client;
+
+    public function setUp()
+    {
+        $this->client = $this->prophesize(Client::class);
+        $this->ipResolver = new IpLocationResolver($this->client->reveal());
+    }
+
+    /**
+     * @test
+     */
+    public function correctIpReturnsDecodedInfo()
+    {
+        $expected = [
+            'foo' => 'bar',
+            'baz' => 'foo',
+        ];
+        $response = new Response();
+        $response->getBody()->write(json_encode($expected));
+        $response->getBody()->rewind();
+
+        $this->client->get('http://freegeoip.net/json/1.2.3.4')->willReturn($response)
+                                                               ->shouldBeCalledTimes(1);
+        $this->assertEquals($expected, $this->ipResolver->resolveIpLocation('1.2.3.4'));
+    }
+
+    /**
+     * @test
+     * @expectedException \Shlinkio\Shlink\Common\Exception\WrongIpException
+     */
+    public function guzzleExceptionThrowsShlinkException()
+    {
+        $this->client->get('http://freegeoip.net/json/1.2.3.4')->willThrow(new TransferException())
+                                                               ->shouldBeCalledTimes(1);
+        $this->ipResolver->resolveIpLocation('1.2.3.4');
+    }
+}
diff --git a/module/Common/test/Twig/Extension/TranslatorExtensionTest.php b/module/Common/test/Twig/Extension/TranslatorExtensionTest.php
new file mode 100644
index 00000000..06b5a584
--- /dev/null
+++ b/module/Common/test/Twig/Extension/TranslatorExtensionTest.php
@@ -0,0 +1,70 @@
+<?php
+namespace ShlinkioTest\Shlink\Common\Twig\Extension;
+
+use PHPUnit_Framework_TestCase as TestCase;
+use Prophecy\Argument;
+use Prophecy\Prophecy\ObjectProphecy;
+use Shlinkio\Shlink\Common\Twig\Extension\TranslatorExtension;
+use Zend\I18n\Translator\Translator;
+
+class TranslatorExtensionTest extends TestCase
+{
+    /**
+     * @var TranslatorExtension
+     */
+    protected $extension;
+    /**
+     * @var ObjectProphecy
+     */
+    protected $translator;
+
+    public function setUp()
+    {
+        $this->translator = $this->prophesize(Translator::class);
+        $this->extension = new TranslatorExtension($this->translator->reveal());
+    }
+
+    /**
+     * @test
+     */
+    public function extensionNameIsClassName()
+    {
+        $this->assertEquals(TranslatorExtension::class, $this->extension->getName());
+    }
+
+    /**
+     * @test
+     */
+    public function properFunctionsAreReturned()
+    {
+        $funcs = $this->extension->getFunctions();
+        $this->assertCount(2, $funcs);
+        foreach ($funcs as $func) {
+            $this->assertInstanceOf(\Twig_SimpleFunction::class, $func);
+        }
+    }
+
+    /**
+     * @test
+     */
+    public function translateFallbacksToTranslator()
+    {
+        $this->translator->translate('foo', 'default', null)->shouldBeCalledTimes(1);
+        $this->extension->translate('foo');
+
+        $this->translator->translate('bar', 'baz', 'en')->shouldBeCalledTimes(1);
+        $this->extension->translate('bar', 'baz', 'en');
+    }
+
+    /**
+     * @test
+     */
+    public function translatePluralFallbacksToTranslator()
+    {
+        $this->translator->translatePlural('foo', 'bar', 'baz', 'default', null)->shouldBeCalledTimes(1);
+        $this->extension->translatePlural('foo', 'bar', 'baz');
+
+        $this->translator->translatePlural('foo', 'bar', 'baz', 'another', 'en')->shouldBeCalledTimes(1);
+        $this->extension->translatePlural('foo', 'bar', 'baz', 'another', 'en');
+    }
+}
diff --git a/module/Common/test/Util/DateRangeTest.php b/module/Common/test/Util/DateRangeTest.php
new file mode 100644
index 00000000..4ed1586e
--- /dev/null
+++ b/module/Common/test/Util/DateRangeTest.php
@@ -0,0 +1,32 @@
+<?php
+namespace ShlinkioTest\Shlink\Common\Util;
+
+use PHPUnit_Framework_TestCase as TestCase;
+use Shlinkio\Shlink\Common\Util\DateRange;
+
+class DateRangeTest extends TestCase
+{
+    /**
+     * @test
+     */
+    public function defaultConstructorSetDatesToNull()
+    {
+        $range = new DateRange();
+        $this->assertNull($range->getStartDate());
+        $this->assertNull($range->getEndDate());
+        $this->assertTrue($range->isEmpty());
+    }
+
+    /**
+     * @test
+     */
+    public function providedDatesAreSet()
+    {
+        $startDate = new \DateTime();
+        $endDate = new \DateTime();
+        $range = new DateRange($startDate, $endDate);
+        $this->assertSame($startDate, $range->getStartDate());
+        $this->assertSame($endDate, $range->getEndDate());
+        $this->assertFalse($range->isEmpty());
+    }
+}
diff --git a/module/Core/src/Action/RedirectAction.php b/module/Core/src/Action/RedirectAction.php
index 122f7f29..031aa0fe 100644
--- a/module/Core/src/Action/RedirectAction.php
+++ b/module/Core/src/Action/RedirectAction.php
@@ -70,10 +70,10 @@ class RedirectAction implements MiddlewareInterface
             // If provided shortCode does not belong to a valid long URL, dispatch next middleware, which will trigger
             // a not-found error
             if (! isset($longUrl)) {
-                return $out($request, $response->withStatus(404), 'Not found');
+                return $this->notFoundResponse($request, $response, $out);
             }
 
-            // Track visit to this shortcode
+            // Track visit to this short code
             $this->visitTracker->track($shortCode);
 
             // Return a redirect response to the long URL.
@@ -81,7 +81,18 @@ class RedirectAction implements MiddlewareInterface
             return new RedirectResponse($longUrl);
         } catch (\Exception $e) {
             // In case of error, dispatch 404 error
-            return $out($request, $response);
+            return $this->notFoundResponse($request, $response, $out);
         }
     }
+
+    /**
+     * @param Request $request
+     * @param Response $response
+     * @param callable $out
+     * @return Response
+     */
+    protected function notFoundResponse(Request $request, Response $response, callable $out)
+    {
+        return $out($request, $response->withStatus(404), 'Not Found');
+    }
 }
diff --git a/module/Core/test/Action/RedirectActionTest.php b/module/Core/test/Action/RedirectActionTest.php
new file mode 100644
index 00000000..434189fc
--- /dev/null
+++ b/module/Core/test/Action/RedirectActionTest.php
@@ -0,0 +1,104 @@
+<?php
+namespace ShlinkioTest\Shlink\Core\Action;
+
+use PHPUnit_Framework_TestCase as TestCase;
+use Prophecy\Argument;
+use Prophecy\Prophecy\ObjectProphecy;
+use Psr\Http\Message\ResponseInterface;
+use Psr\Http\Message\ServerRequestInterface;
+use Shlinkio\Shlink\Core\Action\RedirectAction;
+use Shlinkio\Shlink\Core\Service\UrlShortener;
+use Shlinkio\Shlink\Core\Service\VisitsTracker;
+use Zend\Diactoros\Response;
+use Zend\Diactoros\ServerRequestFactory;
+
+class RedirectActionTest extends TestCase
+{
+    /**
+     * @var RedirectAction
+     */
+    protected $action;
+    /**
+     * @var ObjectProphecy
+     */
+    protected $urlShortener;
+
+    public function setUp()
+    {
+        $this->urlShortener = $this->prophesize(UrlShortener::class);
+        $visitTracker = $this->prophesize(VisitsTracker::class);
+        $visitTracker->track(Argument::any());
+        $this->action = new RedirectAction($this->urlShortener->reveal(), $visitTracker->reveal());
+    }
+
+    /**
+     * @test
+     */
+    public function redirectionIsPerformedToLongUrl()
+    {
+        $shortCode = 'abc123';
+        $expectedUrl = 'http://domain.com/foo/bar';
+        $this->urlShortener->shortCodeToUrl($shortCode)->willReturn($expectedUrl)
+                                                       ->shouldBeCalledTimes(1);
+
+        $request = ServerRequestFactory::fromGlobals()->withAttribute('shortCode', $shortCode);
+        $response = $this->action->__invoke($request, new Response());
+
+        $this->assertInstanceOf(Response\RedirectResponse::class, $response);
+        $this->assertEquals(302, $response->getStatusCode());
+        $this->assertTrue($response->hasHeader('Location'));
+        $this->assertEquals($expectedUrl, $response->getHeaderLine('Location'));
+    }
+
+    /**
+     * @test
+     */
+    public function nextErrorMiddlewareIsInvokedIfLongUrlIsNotFound()
+    {
+        $shortCode = 'abc123';
+        $this->urlShortener->shortCodeToUrl($shortCode)->willReturn(null)
+                           ->shouldBeCalledTimes(1);
+
+        $request = ServerRequestFactory::fromGlobals()->withAttribute('shortCode', $shortCode);
+        $originalResponse = new Response();
+        $test = $this;
+        $this->action->__invoke($request, $originalResponse, function (
+            ServerRequestInterface $req,
+            ResponseInterface $resp,
+            $error
+        ) use (
+            $test,
+            $request
+        ) {
+            $test->assertSame($request, $req);
+            $test->assertEquals(404, $resp->getStatusCode());
+            $test->assertEquals('Not Found', $error);
+        });
+    }
+
+    /**
+     * @test
+     */
+    public function nextErrorMiddlewareIsInvokedIfAnExceptionIsThrown()
+    {
+        $shortCode = 'abc123';
+        $this->urlShortener->shortCodeToUrl($shortCode)->willThrow(\Exception::class)
+                                                       ->shouldBeCalledTimes(1);
+
+        $request = ServerRequestFactory::fromGlobals()->withAttribute('shortCode', $shortCode);
+        $originalResponse = new Response();
+        $test = $this;
+        $this->action->__invoke($request, $originalResponse, function (
+            ServerRequestInterface $req,
+            ResponseInterface $resp,
+            $error
+        ) use (
+            $test,
+            $request
+        ) {
+            $test->assertSame($request, $req);
+            $test->assertEquals(404, $resp->getStatusCode());
+            $test->assertEquals('Not Found', $error);
+        });
+    }
+}
diff --git a/module/Core/test/ConfigProviderTest.php b/module/Core/test/ConfigProviderTest.php
new file mode 100644
index 00000000..fdd41cad
--- /dev/null
+++ b/module/Core/test/ConfigProviderTest.php
@@ -0,0 +1,32 @@
+<?php
+namespace ShlinkioTest\Shlink\Core;
+
+use PHPUnit_Framework_TestCase as TestCase;
+use Shlinkio\Shlink\Core\ConfigProvider;
+
+class ConfigProviderTest extends TestCase
+{
+    /**
+     * @var ConfigProvider
+     */
+    protected $configProvider;
+
+    public function setUp()
+    {
+        $this->configProvider = new ConfigProvider();
+    }
+
+    /**
+     * @test
+     */
+    public function properConfigIsReturned()
+    {
+        $config = $this->configProvider->__invoke();
+
+        $this->assertArrayHasKey('routes', $config);
+        $this->assertArrayHasKey('services', $config);
+        $this->assertArrayHasKey('templates', $config);
+        $this->assertArrayHasKey('translator', $config);
+        $this->assertArrayHasKey('zend-expressive', $config);
+    }
+}
diff --git a/module/Core/test/Service/VisitServiceTest.php b/module/Core/test/Service/VisitServiceTest.php
new file mode 100644
index 00000000..2ecf0a45
--- /dev/null
+++ b/module/Core/test/Service/VisitServiceTest.php
@@ -0,0 +1,49 @@
+<?php
+namespace ShlinkioTest\Shlink\Core\Service;
+
+use Doctrine\ORM\EntityManager;
+use PHPUnit_Framework_TestCase as TestCase;
+use Prophecy\Prophecy\ObjectProphecy;
+use Shlinkio\Shlink\Core\Entity\Visit;
+use Shlinkio\Shlink\Core\Repository\VisitRepository;
+use Shlinkio\Shlink\Core\Service\VisitService;
+
+class VisitServiceTest extends TestCase
+{
+    /**
+     * @var VisitService
+     */
+    protected $visitService;
+    /**
+     * @var ObjectProphecy
+     */
+    protected $em;
+
+    public function setUp()
+    {
+        $this->em = $this->prophesize(EntityManager::class);
+        $this->visitService = new VisitService($this->em->reveal());
+    }
+
+    /**
+     * @test
+     */
+    public function saveVisitsPersistsProvidedVisit()
+    {
+        $visit = new Visit();
+        $this->em->persist($visit)->shouldBeCalledTimes(1);
+        $this->em->flush()->shouldBeCalledTimes(1);
+        $this->visitService->saveVisit($visit);
+    }
+
+    /**
+     * @test
+     */
+    public function getUnlocatedVisitsFallbacksToRepository()
+    {
+        $repo = $this->prophesize(VisitRepository::class);
+        $repo->findUnlocatedVisits()->shouldBeCalledTimes(1);
+        $this->em->getRepository(Visit::class)->willReturn($repo->reveal())->shouldBeCalledTimes(1);
+        $this->visitService->getUnlocatedVisits();
+    }
+}
diff --git a/module/Core/test/Service/VisitsTrackerTest.php b/module/Core/test/Service/VisitsTrackerTest.php
index 2a441e04..4d8a68fe 100644
--- a/module/Core/test/Service/VisitsTrackerTest.php
+++ b/module/Core/test/Service/VisitsTrackerTest.php
@@ -5,11 +5,29 @@ use Doctrine\ORM\EntityManager;
 use Doctrine\ORM\EntityRepository;
 use PHPUnit_Framework_TestCase as TestCase;
 use Prophecy\Argument;
+use Prophecy\Prophecy\ObjectProphecy;
 use Shlinkio\Shlink\Core\Entity\ShortUrl;
+use Shlinkio\Shlink\Core\Entity\Visit;
+use Shlinkio\Shlink\Core\Repository\VisitRepository;
 use Shlinkio\Shlink\Core\Service\VisitsTracker;
 
 class VisitsTrackerTest extends TestCase
 {
+    /**
+     * @var VisitsTracker
+     */
+    protected $visitsTracker;
+    /**
+     * @var ObjectProphecy
+     */
+    protected $em;
+
+    public function setUp()
+    {
+        $this->em = $this->prophesize(EntityManager::class);
+        $this->visitsTracker  = new VisitsTracker($this->em->reveal());
+    }
+
     /**
      * @test
      */
@@ -19,12 +37,32 @@ class VisitsTrackerTest extends TestCase
         $repo = $this->prophesize(EntityRepository::class);
         $repo->findOneBy(['shortCode' => $shortCode])->willReturn(new ShortUrl());
 
-        $em = $this->prophesize(EntityManager::class);
-        $em->getRepository(ShortUrl::class)->willReturn($repo->reveal())->shouldBeCalledTimes(1);
-        $em->persist(Argument::any())->shouldBeCalledTimes(1);
-        $em->flush()->shouldBeCalledTimes(1);
+        $this->em->getRepository(ShortUrl::class)->willReturn($repo->reveal())->shouldBeCalledTimes(1);
+        $this->em->persist(Argument::any())->shouldBeCalledTimes(1);
+        $this->em->flush()->shouldBeCalledTimes(1);
 
-        $visitsTracker = new VisitsTracker($em->reveal());
-        $visitsTracker->track($shortCode);
+        $this->visitsTracker->track($shortCode);
+    }
+
+    /**
+     * @test
+     */
+    public function infoReturnsVisistForCertainShortCode()
+    {
+        $shortCode = '123ABC';
+        $shortUrl = (new ShortUrl())->setOriginalUrl('http://domain.com/foo/bar');
+        $repo = $this->prophesize(EntityRepository::class);
+        $repo->findOneBy(['shortCode' => $shortCode])->willReturn($shortUrl);
+        $this->em->getRepository(ShortUrl::class)->willReturn($repo->reveal())->shouldBeCalledTimes(1);
+
+        $list = [
+            new Visit(),
+            new Visit(),
+        ];
+        $repo2 = $this->prophesize(VisitRepository::class);
+        $repo2->findVisitsByShortUrl($shortUrl, null)->willReturn($list);
+        $this->em->getRepository(Visit::class)->willReturn($repo2->reveal())->shouldBeCalledTimes(1);
+
+        $this->assertEquals($list, $this->visitsTracker->info($shortCode));
     }
 }
diff --git a/module/Rest/config/error-handler.config.php b/module/Rest/config/error-handler.config.php
index 4b5b7e75..fef71303 100644
--- a/module/Rest/config/error-handler.config.php
+++ b/module/Rest/config/error-handler.config.php
@@ -1,5 +1,5 @@
 <?php
-use Shlinkio\Shlink\Rest\Expressive\JsonErrorHandler;
+use Shlinkio\Shlink\Rest\ErrorHandler\JsonErrorHandler;
 
 return [
 
diff --git a/module/Rest/src/Expressive/JsonErrorHandler.php b/module/Rest/src/ErrorHandler/JsonErrorHandler.php
similarity index 92%
rename from module/Rest/src/Expressive/JsonErrorHandler.php
rename to module/Rest/src/ErrorHandler/JsonErrorHandler.php
index 9294ec24..248bb6ae 100644
--- a/module/Rest/src/Expressive/JsonErrorHandler.php
+++ b/module/Rest/src/ErrorHandler/JsonErrorHandler.php
@@ -1,9 +1,9 @@
 <?php
-namespace Shlinkio\Shlink\Rest\Expressive;
+namespace Shlinkio\Shlink\Rest\ErrorHandler;
 
 use Psr\Http\Message\ServerRequestInterface as Request;
 use Psr\Http\Message\ResponseInterface as Response;
-use Shlinkio\Shlink\Common\Expressive\ErrorHandlerInterface;
+use Shlinkio\Shlink\Common\ErrorHandler\ErrorHandlerInterface;
 use Zend\Diactoros\Response\JsonResponse;
 use Zend\Expressive\Router\RouteResult;
 
diff --git a/module/Rest/test/Action/AuthenticateActionTest.php b/module/Rest/test/Action/AuthenticateActionTest.php
new file mode 100644
index 00000000..d61da421
--- /dev/null
+++ b/module/Rest/test/Action/AuthenticateActionTest.php
@@ -0,0 +1,75 @@
+<?php
+namespace ShlinkioTest\Shlink\Rest\Action;
+
+use PHPUnit_Framework_TestCase as TestCase;
+use Prophecy\Prophecy\ObjectProphecy;
+use Shlinkio\Shlink\Core\Entity\RestToken;
+use Shlinkio\Shlink\Rest\Action\AuthenticateAction;
+use Shlinkio\Shlink\Rest\Exception\AuthenticationException;
+use Shlinkio\Shlink\Rest\Service\RestTokenService;
+use Zend\Diactoros\Response;
+use Zend\Diactoros\ServerRequestFactory;
+use Zend\I18n\Translator\Translator;
+
+class AuthenticateActionTest extends TestCase
+{
+    /**
+     * @var AuthenticateAction
+     */
+    protected $action;
+    /**
+     * @var ObjectProphecy
+     */
+    protected $tokenService;
+
+    public function setUp()
+    {
+        $this->tokenService = $this->prophesize(RestTokenService::class);
+        $this->action = new AuthenticateAction($this->tokenService->reveal(), Translator::factory([]));
+    }
+
+    /**
+     * @test
+     */
+    public function notProvidingAuthDataReturnsError()
+    {
+        $resp = $this->action->__invoke(ServerRequestFactory::fromGlobals(), new Response());
+        $this->assertEquals(400, $resp->getStatusCode());
+    }
+
+    /**
+     * @test
+     */
+    public function properCredentialsReturnTokenInResponse()
+    {
+        $this->tokenService->createToken('foo', 'bar')->willReturn(
+            (new RestToken())->setToken('abc-ABC')
+        )->shouldBeCalledTimes(1);
+
+        $request = ServerRequestFactory::fromGlobals()->withParsedBody([
+            'username' => 'foo',
+            'password' => 'bar',
+        ]);
+        $response = $this->action->__invoke($request, new Response());
+        $this->assertEquals(200, $response->getStatusCode());
+
+        $response->getBody()->rewind();
+        $this->assertEquals(['token' => 'abc-ABC'], json_decode($response->getBody()->getContents(), true));
+    }
+
+    /**
+     * @test
+     */
+    public function authenticationExceptionsReturnErrorResponse()
+    {
+        $this->tokenService->createToken('foo', 'bar')->willThrow(new AuthenticationException())
+                                                      ->shouldBeCalledTimes(1);
+
+        $request = ServerRequestFactory::fromGlobals()->withParsedBody([
+            'username' => 'foo',
+            'password' => 'bar',
+        ]);
+        $response = $this->action->__invoke($request, new Response());
+        $this->assertEquals(401, $response->getStatusCode());
+    }
+}
diff --git a/module/Rest/test/Action/CreateShortcodeActionTest.php b/module/Rest/test/Action/CreateShortcodeActionTest.php
new file mode 100644
index 00000000..dcc56bf6
--- /dev/null
+++ b/module/Rest/test/Action/CreateShortcodeActionTest.php
@@ -0,0 +1,92 @@
+<?php
+namespace ShlinkioTest\Shlink\Rest\Action;
+
+use PHPUnit_Framework_TestCase as TestCase;
+use Prophecy\Argument;
+use Prophecy\Prophecy\ObjectProphecy;
+use Shlinkio\Shlink\Core\Exception\InvalidUrlException;
+use Shlinkio\Shlink\Core\Service\UrlShortener;
+use Shlinkio\Shlink\Rest\Action\CreateShortcodeAction;
+use Shlinkio\Shlink\Rest\Util\RestUtils;
+use Zend\Diactoros\Response;
+use Zend\Diactoros\ServerRequestFactory;
+use Zend\Diactoros\Uri;
+use Zend\I18n\Translator\Translator;
+
+class CreateShortcodeActionTest extends TestCase
+{
+    /**
+     * @var CreateShortcodeAction
+     */
+    protected $action;
+    /**
+     * @var ObjectProphecy
+     */
+    protected $urlShortener;
+
+    public function setUp()
+    {
+        $this->urlShortener = $this->prophesize(UrlShortener::class);
+        $this->action = new CreateShortcodeAction($this->urlShortener->reveal(), Translator::factory([]), [
+            'schema' => 'http',
+            'hostname' => 'foo.com',
+        ]);
+    }
+
+    /**
+     * @test
+     */
+    public function missingLongUrlParamReturnsError()
+    {
+        $response = $this->action->__invoke(ServerRequestFactory::fromGlobals(), new Response());
+        $this->assertEquals(400, $response->getStatusCode());
+    }
+
+    /**
+     * @test
+     */
+    public function properShortcodeConversionReturnsData()
+    {
+        $this->urlShortener->urlToShortCode(Argument::type(Uri::class))->willReturn('abc123')
+                                                                       ->shouldBeCalledTimes(1);
+
+        $request = ServerRequestFactory::fromGlobals()->withParsedBody([
+            'longUrl' => 'http://www.domain.com/foo/bar',
+        ]);
+        $response = $this->action->__invoke($request, new Response());
+        $this->assertEquals(200, $response->getStatusCode());
+        $this->assertTrue(strpos($response->getBody()->getContents(), 'http://foo.com/abc123') > 0);
+    }
+
+    /**
+     * @test
+     */
+    public function anInvalidUrlReturnsError()
+    {
+        $this->urlShortener->urlToShortCode(Argument::type(Uri::class))->willThrow(InvalidUrlException::class)
+                                                                       ->shouldBeCalledTimes(1);
+
+        $request = ServerRequestFactory::fromGlobals()->withParsedBody([
+            'longUrl' => 'http://www.domain.com/foo/bar',
+        ]);
+        $response = $this->action->__invoke($request, new Response());
+        $this->assertEquals(400, $response->getStatusCode());
+        $this->assertTrue(strpos($response->getBody()->getContents(), RestUtils::INVALID_URL_ERROR) > 0);
+    }
+
+    /**
+     * @test
+     */
+    public function aGenericExceptionWillReturnError()
+    {
+        $this->urlShortener->urlToShortCode(Argument::type(Uri::class))->willThrow(\Exception::class)
+                                                                       ->shouldBeCalledTimes(1);
+
+        $request = ServerRequestFactory::fromGlobals()->withParsedBody([
+            'longUrl' => 'http://www.domain.com/foo/bar',
+        ]);
+        $response = $this->action->__invoke($request, new Response());
+        $this->assertEquals(500, $response->getStatusCode());
+        $this->assertTrue(strpos($response->getBody()->getContents(), RestUtils::UNKNOWN_ERROR) > 0);
+    }
+}
diff --git a/module/Rest/test/Action/GetVisitsActionTest.php b/module/Rest/test/Action/GetVisitsActionTest.php
new file mode 100644
index 00000000..901c549e
--- /dev/null
+++ b/module/Rest/test/Action/GetVisitsActionTest.php
@@ -0,0 +1,99 @@
+<?php
+namespace ShlinkioTest\Shlink\Rest\Action;
+
+use PHPUnit_Framework_TestCase as TestCase;
+use Prophecy\Argument;
+use Prophecy\Prophecy\ObjectProphecy;
+use Shlinkio\Shlink\Common\Exception\InvalidArgumentException;
+use Shlinkio\Shlink\Common\Util\DateRange;
+use Shlinkio\Shlink\Core\Service\VisitsTracker;
+use Shlinkio\Shlink\Rest\Action\GetVisitsAction;
+use Zend\Diactoros\Response;
+use Zend\Diactoros\ServerRequestFactory;
+use Zend\I18n\Translator\Translator;
+
+class GetVisitsActionTest extends TestCase
+{
+    /**
+     * @var GetVisitsAction
+     */
+    protected $action;
+    /**
+     * @var ObjectProphecy
+     */
+    protected $visitsTracker;
+
+    public function setUp()
+    {
+        $this->visitsTracker = $this->prophesize(VisitsTracker::class);
+        $this->action = new GetVisitsAction($this->visitsTracker->reveal(), Translator::factory([]));
+    }
+
+    /**
+     * @test
+     */
+    public function providingCorrectShortCodeReturnsVisits()
+    {
+        $shortCode = 'abc123';
+        $this->visitsTracker->info($shortCode, Argument::type(DateRange::class))->willReturn([])
+                                                                                ->shouldBeCalledTimes(1);
+
+        $response = $this->action->__invoke(
+            ServerRequestFactory::fromGlobals()->withAttribute('shortCode', $shortCode),
+            new Response()
+        );
+        $this->assertEquals(200, $response->getStatusCode());
+    }
+
+    /**
+     * @test
+     */
+    public function providingInvalidShortCodeReturnsError()
+    {
+        $shortCode = 'abc123';
+        $this->visitsTracker->info($shortCode, Argument::type(DateRange::class))->willThrow(
+            InvalidArgumentException::class
+        )->shouldBeCalledTimes(1);
+
+        $response = $this->action->__invoke(
+            ServerRequestFactory::fromGlobals()->withAttribute('shortCode', $shortCode),
+            new Response()
+        );
+        $this->assertEquals(400, $response->getStatusCode());
+    }
+
+    /**
+     * @test
+     */
+    public function unexpectedExceptionWillReturnError()
+    {
+        $shortCode = 'abc123';
+        $this->visitsTracker->info($shortCode, Argument::type(DateRange::class))->willThrow(
+            \Exception::class
+        )->shouldBeCalledTimes(1);
+
+        $response = $this->action->__invoke(
+            ServerRequestFactory::fromGlobals()->withAttribute('shortCode', $shortCode),
+            new Response()
+        );
+        $this->assertEquals(500, $response->getStatusCode());
+    }
+
+    /**
+     * @test
+     */
+    public function datesAreReadFromQuery()
+    {
+        $shortCode = 'abc123';
+        $this->visitsTracker->info($shortCode, new DateRange(null, new \DateTime('2016-01-01 00:00:00')))
+            ->willReturn([])
+            ->shouldBeCalledTimes(1);
+
+        $response = $this->action->__invoke(
+            ServerRequestFactory::fromGlobals()->withAttribute('shortCode', $shortCode)
+                                               ->withQueryParams(['endDate' => '2016-01-01 00:00:00']),
+            new Response()
+        );
+        $this->assertEquals(200, $response->getStatusCode());
+    }
+}
diff --git a/module/Rest/test/Action/ListShortcodesActionTest.php b/module/Rest/test/Action/ListShortcodesActionTest.php
new file mode 100644
index 00000000..b5ec0c9d
--- /dev/null
+++ b/module/Rest/test/Action/ListShortcodesActionTest.php
@@ -0,0 +1,66 @@
+<?php
+namespace ShlinkioTest\Shlink\Rest\Action;
+
+use PHPUnit_Framework_TestCase as TestCase;
+use Prophecy\Prophecy\ObjectProphecy;
+use Shlinkio\Shlink\Core\Service\ShortUrlService;
+use Shlinkio\Shlink\Rest\Action\ListShortcodesAction;
+use Zend\Diactoros\Response;
+use Zend\Diactoros\ServerRequestFactory;
+use Zend\I18n\Translator\Translator;
+use Zend\Paginator\Adapter\ArrayAdapter;
+use Zend\Paginator\Paginator;
+
+class ListShortcodesActionTest extends TestCase
+{
+    /**
+     * @var ListShortcodesAction
+     */
+    protected $action;
+    /**
+     * @var ObjectProphecy
+     */
+    protected $service;
+
+    public function setUp()
+    {
+        $this->service = $this->prophesize(ShortUrlService::class);
+        $this->action = new ListShortcodesAction($this->service->reveal(), Translator::factory([]));
+    }
+
+    /**
+     * @test
+     */
+    public function properListReturnsSuccessResponse()
+    {
+        $page = 3;
+        $this->service->listShortUrls($page)->willReturn(new Paginator(new ArrayAdapter()))
+                                            ->shouldBeCalledTimes(1);
+
+        $response = $this->action->__invoke(
+            ServerRequestFactory::fromGlobals()->withQueryParams([
+                'page' => $page,
+            ]),
+            new Response()
+        );
+        $this->assertEquals(200, $response->getStatusCode());
+    }
+
+    /**
+     * @test
+     */
+    public function anExceptionsReturnsErrorResponse()
+    {
+        $page = 3;
+        $this->service->listShortUrls($page)->willThrow(\Exception::class)
+                                            ->shouldBeCalledTimes(1);
+
+        $response = $this->action->__invoke(
+            ServerRequestFactory::fromGlobals()->withQueryParams([
+                'page' => $page,
+            ]),
+            new Response()
+        );
+        $this->assertEquals(500, $response->getStatusCode());
+    }
+}
diff --git a/module/Rest/test/Action/ResolveUrlActionTest.php b/module/Rest/test/Action/ResolveUrlActionTest.php
new file mode 100644
index 00000000..0bd3bded
--- /dev/null
+++ b/module/Rest/test/Action/ResolveUrlActionTest.php
@@ -0,0 +1,90 @@
+<?php
+namespace ShlinkioTest\Shlink\Rest\Action;
+
+use PHPUnit_Framework_TestCase as TestCase;
+use Prophecy\Prophecy\ObjectProphecy;
+use Shlinkio\Shlink\Core\Exception\InvalidShortCodeException;
+use Shlinkio\Shlink\Core\Service\UrlShortener;
+use Shlinkio\Shlink\Rest\Action\ResolveUrlAction;
+use Shlinkio\Shlink\Rest\Util\RestUtils;
+use Zend\Diactoros\Response;
+use Zend\Diactoros\ServerRequestFactory;
+use Zend\I18n\Translator\Translator;
+
+class ResolveUrlActionTest extends TestCase
+{
+    /**
+     * @var ResolveUrlAction
+     */
+    protected $action;
+    /**
+     * @var ObjectProphecy
+     */
+    protected $urlShortener;
+
+    public function setUp()
+    {
+        $this->urlShortener = $this->prophesize(UrlShortener::class);
+        $this->action = new ResolveUrlAction($this->urlShortener->reveal(), Translator::factory([]));
+    }
+
+    /**
+     * @test
+     */
+    public function incorrectShortCodeReturnsError()
+    {
+        $shortCode = 'abc123';
+        $this->urlShortener->shortCodeToUrl($shortCode)->willReturn(null)
+                                                       ->shouldBeCalledTimes(1);
+
+        $request = ServerRequestFactory::fromGlobals()->withAttribute('shortCode', $shortCode);
+        $response = $this->action->__invoke($request, new Response());
+        $this->assertEquals(400, $response->getStatusCode());
+        $this->assertTrue(strpos($response->getBody()->getContents(), RestUtils::INVALID_ARGUMENT_ERROR) > 0);
+    }
+
+    /**
+     * @test
+     */
+    public function correctShortCodeReturnsSuccess()
+    {
+        $shortCode = 'abc123';
+        $this->urlShortener->shortCodeToUrl($shortCode)->willReturn('http://domain.com/foo/bar')
+                                                       ->shouldBeCalledTimes(1);
+
+        $request = ServerRequestFactory::fromGlobals()->withAttribute('shortCode', $shortCode);
+        $response = $this->action->__invoke($request, new Response());
+        $this->assertEquals(200, $response->getStatusCode());
+        $this->assertTrue(strpos($response->getBody()->getContents(), 'http://domain.com/foo/bar') > 0);
+    }
+
+    /**
+     * @test
+     */
+    public function invalidShortCodeExceptionReturnsError()
+    {
+        $shortCode = 'abc123';
+        $this->urlShortener->shortCodeToUrl($shortCode)->willThrow(InvalidShortCodeException::class)
+                                                       ->shouldBeCalledTimes(1);
+
+        $request = ServerRequestFactory::fromGlobals()->withAttribute('shortCode', $shortCode);
+        $response = $this->action->__invoke($request, new Response());
+        $this->assertEquals(400, $response->getStatusCode());
+        $this->assertTrue(strpos($response->getBody()->getContents(), RestUtils::INVALID_SHORTCODE_ERROR) > 0);
+    }
+
+    /**
+     * @test
+     */
+    public function unexpectedExceptionWillReturnError()
+    {
+        $shortCode = 'abc123';
+        $this->urlShortener->shortCodeToUrl($shortCode)->willThrow(\Exception::class)
+                                                       ->shouldBeCalledTimes(1);
+
+        $request = ServerRequestFactory::fromGlobals()->withAttribute('shortCode', $shortCode);
+        $response = $this->action->__invoke($request, new Response());
+        $this->assertEquals(500, $response->getStatusCode());
+        $this->assertTrue(strpos($response->getBody()->getContents(), RestUtils::UNKNOWN_ERROR) > 0);
+    }
+}
diff --git a/module/Rest/test/ConfigProviderTest.php b/module/Rest/test/ConfigProviderTest.php
new file mode 100644
index 00000000..377c845f
--- /dev/null
+++ b/module/Rest/test/ConfigProviderTest.php
@@ -0,0 +1,33 @@
+<?php
+namespace ShlinkioTest\Shlink\Rest;
+
+use PHPUnit_Framework_TestCase as TestCase;
+use Shlinkio\Shlink\Rest\ConfigProvider;
+
+class ConfigProviderTest extends TestCase
+{
+    /**
+     * @var ConfigProvider
+     */
+    protected $configProvider;
+
+    public function setUp()
+    {
+        $this->configProvider = new ConfigProvider();
+    }
+
+    /**
+     * @test
+     */
+    public function properConfigIsReturned()
+    {
+        $config = $this->configProvider->__invoke();
+
+        $this->assertArrayHasKey('error_handler', $config);
+        $this->assertArrayHasKey('middleware_pipeline', $config);
+        $this->assertArrayHasKey('rest', $config);
+        $this->assertArrayHasKey('routes', $config);
+        $this->assertArrayHasKey('services', $config);
+        $this->assertArrayHasKey('translator', $config);
+    }
+}
diff --git a/module/Rest/test/ErrorHandler/JsonErrorHandlerTest.php b/module/Rest/test/ErrorHandler/JsonErrorHandlerTest.php
new file mode 100644
index 00000000..ea1eee80
--- /dev/null
+++ b/module/Rest/test/ErrorHandler/JsonErrorHandlerTest.php
@@ -0,0 +1,79 @@
+<?php
+namespace ShlinkioTest\Shlink\Rest\ErrorHandler;
+
+use PHPUnit_Framework_TestCase as TestCase;
+use Shlinkio\Shlink\Rest\ErrorHandler\JsonErrorHandler;
+use Zend\Diactoros\Response;
+use Zend\Diactoros\ServerRequestFactory;
+use Zend\Expressive\Router\RouteResult;
+
+class JsonErrorHandlerTest extends TestCase
+{
+    /**
+     * @var JsonErrorHandler
+     */
+    protected $errorHandler;
+
+    public function setUp()
+    {
+        $this->errorHandler = new JsonErrorHandler();
+    }
+
+    /**
+     * @test
+     */
+    public function noMatchedRouteReturnsNotFoundResponse()
+    {
+        $response = $this->errorHandler->__invoke(ServerRequestFactory::fromGlobals(), new Response());
+        $this->assertInstanceOf(Response\JsonResponse::class, $response);
+        $this->assertEquals(404, $response->getStatusCode());
+    }
+
+    /**
+     * @test
+     */
+    public function matchedRouteWithErrorReturnsMethodNotAllowedResponse()
+    {
+        $response = $this->errorHandler->__invoke(
+            ServerRequestFactory::fromGlobals(),
+            (new Response())->withStatus(405),
+            405
+        );
+        $this->assertInstanceOf(Response\JsonResponse::class, $response);
+        $this->assertEquals(405, $response->getStatusCode());
+    }
+
+    /**
+     * @test
+     */
+    public function responseWithErrorKeepsStatus()
+    {
+        $response = $this->errorHandler->__invoke(
+            ServerRequestFactory::fromGlobals()->withAttribute(
+                RouteResult::class,
+                RouteResult::fromRouteMatch('foo', 'bar', [])
+            ),
+            (new Response())->withStatus(401),
+            401
+        );
+        $this->assertInstanceOf(Response\JsonResponse::class, $response);
+        $this->assertEquals(401, $response->getStatusCode());
+    }
+
+    /**
+     * @test
+     */
+    public function responseWithoutErrorReturnsStatus500()
+    {
+        $response = $this->errorHandler->__invoke(
+            ServerRequestFactory::fromGlobals()->withAttribute(
+                RouteResult::class,
+                RouteResult::fromRouteMatch('foo', 'bar', [])
+            ),
+            (new Response())->withStatus(200),
+            'Some error'
+        );
+        $this->assertInstanceOf(Response\JsonResponse::class, $response);
+        $this->assertEquals(500, $response->getStatusCode());
+    }
+}
diff --git a/module/Rest/test/Middleware/CheckAuthenticationMiddlewareTest.php b/module/Rest/test/Middleware/CheckAuthenticationMiddlewareTest.php
new file mode 100644
index 00000000..650d4d2f
--- /dev/null
+++ b/module/Rest/test/Middleware/CheckAuthenticationMiddlewareTest.php
@@ -0,0 +1,134 @@
+<?php
+namespace ShlinkioTest\Shlink\Rest\Middleware;
+
+use PHPUnit_Framework_TestCase as TestCase;
+use Prophecy\Prophecy\ObjectProphecy;
+use Shlinkio\Shlink\Core\Entity\RestToken;
+use Shlinkio\Shlink\Rest\Middleware\CheckAuthenticationMiddleware;
+use Shlinkio\Shlink\Rest\Service\RestTokenService;
+use Zend\Diactoros\Response;
+use Zend\Diactoros\ServerRequestFactory;
+use Zend\Expressive\Router\RouteResult;
+use Zend\I18n\Translator\Translator;
+
+class CheckAuthenticationMiddlewareTest extends TestCase
+{
+    /**
+     * @var CheckAuthenticationMiddleware
+     */
+    protected $middleware;
+    /**
+     * @var ObjectProphecy
+     */
+    protected $tokenService;
+
+    public function setUp()
+    {
+        $this->tokenService = $this->prophesize(RestTokenService::class);
+        $this->middleware = new CheckAuthenticationMiddleware($this->tokenService->reveal(), Translator::factory([]));
+    }
+
+    /**
+     * @test
+     */
+    public function someWhitelistedSituationsFallbackToNextMiddleware()
+    {
+        $request = ServerRequestFactory::fromGlobals();
+        $response = new Response();
+        $isCalled = false;
+        $this->assertFalse($isCalled);
+        $this->middleware->__invoke($request, $response, function ($req, $resp) use (&$isCalled) {
+            $isCalled = true;
+        });
+        $this->assertTrue($isCalled);
+
+        $request = ServerRequestFactory::fromGlobals()->withAttribute(
+            RouteResult::class,
+            RouteResult::fromRouteFailure(['GET'])
+        );
+        $response = new Response();
+        $isCalled = false;
+        $this->assertFalse($isCalled);
+        $this->middleware->__invoke($request, $response, function ($req, $resp) use (&$isCalled) {
+            $isCalled = true;
+        });
+        $this->assertTrue($isCalled);
+
+        $request = ServerRequestFactory::fromGlobals()->withAttribute(
+            RouteResult::class,
+            RouteResult::fromRouteMatch('rest-authenticate', 'foo', [])
+        );
+        $response = new Response();
+        $isCalled = false;
+        $this->assertFalse($isCalled);
+        $this->middleware->__invoke($request, $response, function ($req, $resp) use (&$isCalled) {
+            $isCalled = true;
+        });
+        $this->assertTrue($isCalled);
+
+        $request = ServerRequestFactory::fromGlobals()->withAttribute(
+            RouteResult::class,
+            RouteResult::fromRouteMatch('bar', 'foo', [])
+        )->withMethod('OPTIONS');
+        $response = new Response();
+        $isCalled = false;
+        $this->assertFalse($isCalled);
+        $this->middleware->__invoke($request, $response, function ($req, $resp) use (&$isCalled) {
+            $isCalled = true;
+        });
+        $this->assertTrue($isCalled);
+    }
+
+    /**
+     * @test
+     */
+    public function noHeaderReturnsError()
+    {
+        $request = ServerRequestFactory::fromGlobals()->withAttribute(
+            RouteResult::class,
+            RouteResult::fromRouteMatch('bar', 'foo', [])
+        );
+        $response = $this->middleware->__invoke($request, new Response());
+        $this->assertEquals(401, $response->getStatusCode());
+    }
+
+    /**
+     * @test
+     */
+    public function provideAnExpiredTokenReturnsError()
+    {
+        $authToken = 'ABC-abc';
+        $request = ServerRequestFactory::fromGlobals()->withAttribute(
+            RouteResult::class,
+            RouteResult::fromRouteMatch('bar', 'foo', [])
+        )->withHeader(CheckAuthenticationMiddleware::AUTH_TOKEN_HEADER, $authToken);
+        $this->tokenService->getByToken($authToken)->willReturn(
+            (new RestToken())->setExpirationDate((new \DateTime())->sub(new \DateInterval('P1D')))
+        )->shouldBeCalledTimes(1);
+
+        $response = $this->middleware->__invoke($request, new Response());
+        $this->assertEquals(401, $response->getStatusCode());
+    }
+
+    /**
+     * @test
+     */
+    public function provideCorrectTokenUpdatesExpirationAndFallbacksToNextMiddleware()
+    {
+        $authToken = 'ABC-abc';
+        $restToken = (new RestToken())->setExpirationDate((new \DateTime())->add(new \DateInterval('P1D')));
+        $request = ServerRequestFactory::fromGlobals()->withAttribute(
+            RouteResult::class,
+            RouteResult::fromRouteMatch('bar', 'foo', [])
+        )->withHeader(CheckAuthenticationMiddleware::AUTH_TOKEN_HEADER, $authToken);
+        $this->tokenService->getByToken($authToken)->willReturn($restToken)->shouldBeCalledTimes(1);
+        $this->tokenService->updateExpiration($restToken)->shouldBeCalledTimes(1);
+
+        $isCalled = false;
+        $this->assertFalse($isCalled);
+        $this->middleware->__invoke($request, new Response(), function ($req, $resp) use (&$isCalled) {
+            $isCalled = true;
+        });
+        $this->assertTrue($isCalled);
+    }
+}
diff --git a/module/Rest/test/Service/RestTokenServiceTest.php b/module/Rest/test/Service/RestTokenServiceTest.php
new file mode 100644
index 00000000..d4487ff1
--- /dev/null
+++ b/module/Rest/test/Service/RestTokenServiceTest.php
@@ -0,0 +1,93 @@
+<?php
+namespace ShlinkioTest\Shlink\Rest\Service;
+
+use Doctrine\ORM\EntityManager;
+use Doctrine\ORM\EntityRepository;
+use PHPUnit_Framework_TestCase as TestCase;
+use Prophecy\Argument;
+use Prophecy\Prophecy\ObjectProphecy;
+use Shlinkio\Shlink\Core\Entity\RestToken;
+use Shlinkio\Shlink\Rest\Service\RestTokenService;
+
+class RestTokenServiceTest extends TestCase
+{
+    /**
+     * @var RestTokenService
+     */
+    protected $service;
+    /**
+     * @var ObjectProphecy
+     */
+    protected $em;
+
+    public function setUp()
+    {
+        $this->em = $this->prophesize(EntityManager::class);
+        $this->service = new RestTokenService($this->em->reveal(), [
+            'username' => 'foo',
+            'password' => 'bar',
+        ]);
+    }
+
+    /**
+     * @test
+     */
+    public function tokenIsCreatedIfCredentialsAreCorrect()
+    {
+        $this->em->persist(Argument::type(RestToken::class))->shouldBeCalledTimes(1);
+        $this->em->flush()->shouldBeCalledTimes(1);
+
+        $token = $this->service->createToken('foo', 'bar');
+        $this->assertInstanceOf(RestToken::class, $token);
+        $this->assertFalse($token->isExpired());
+    }
+
+    /**
+     * @test
+     * @expectedException \Shlinkio\Shlink\Rest\Exception\AuthenticationException
+     */
+    public function exceptionIsThrownWhileCreatingTokenWithWrongCredentials()
+    {
+        $this->service->createToken('foo', 'wrong');
+    }
+
+    /**
+     * @test
+     */
+    public function restTokenIsReturnedFromTokenString()
+    {
+        $authToken = 'ABC-abc';
+        $theToken = new RestToken();
+        $repo = $this->prophesize(EntityRepository::class);
+        $repo->findOneBy(['token' => $authToken])->willReturn($theToken)->shouldBeCalledTimes(1);
+        $this->em->getRepository(RestToken::class)->willReturn($repo->reveal())->shouldBeCalledTimes(1);
+
+        $this->assertSame($theToken, $this->service->getByToken($authToken));
+    }
+
+    /**
+     * @test
+     * @expectedException \Shlinkio\Shlink\Common\Exception\InvalidArgumentException
+     */
+    public function exceptionIsThrownWhenRequestingWrongToken()
+    {
+        $authToken = 'ABC-abc';
+        $repo = $this->prophesize(EntityRepository::class);
+        $repo->findOneBy(['token' => $authToken])->willReturn(null)->shouldBeCalledTimes(1);
+        $this->em->getRepository(RestToken::class)->willReturn($repo->reveal())->shouldBeCalledTimes(1);
+
+        $this->service->getByToken($authToken);
+    }
+
+    /**
+     * @test
+     */
+    public function updateExpirationFlushesEntityManager()
+    {
+        $token = $this->prophesize(RestToken::class);
+        $token->updateExpiration()->shouldBeCalledTimes(1);
+        $this->em->flush()->shouldBeCalledTimes(1);
+
+        $this->service->updateExpiration($token->reveal());
+    }
+}
diff --git a/module/Rest/test/Util/RestUtilsTest.php b/module/Rest/test/Util/RestUtilsTest.php
new file mode 100644
index 00000000..d53b6905
--- /dev/null
+++ b/module/Rest/test/Util/RestUtilsTest.php
@@ -0,0 +1,40 @@
+<?php
+namespace ShlinkioTest\Shlink\Rest\Util;
+
+use PHPUnit_Framework_TestCase as TestCase;
+use Shlinkio\Shlink\Common\Exception\InvalidArgumentException;
+use Shlinkio\Shlink\Common\Exception\WrongIpException;
+use Shlinkio\Shlink\Core\Exception\InvalidShortCodeException;
+use Shlinkio\Shlink\Core\Exception\InvalidUrlException;
+use Shlinkio\Shlink\Rest\Exception\AuthenticationException;
+use Shlinkio\Shlink\Rest\Util\RestUtils;
+
+class RestUtilsTest extends TestCase
+{
+    /**
+     * @test
+     */
+    public function correctCodeIsReturnedFromException()
+    {
+        $this->assertEquals(
+            RestUtils::INVALID_SHORTCODE_ERROR,
+            RestUtils::getRestErrorCodeFromException(new InvalidShortCodeException())
+        );
+        $this->assertEquals(
+            RestUtils::INVALID_URL_ERROR,
+            RestUtils::getRestErrorCodeFromException(new InvalidUrlException())
+        );
+        $this->assertEquals(
+            RestUtils::INVALID_ARGUMENT_ERROR,
+            RestUtils::getRestErrorCodeFromException(new InvalidArgumentException())
+        );
+        $this->assertEquals(
+            RestUtils::INVALID_CREDENTIALS_ERROR,
+            RestUtils::getRestErrorCodeFromException(new AuthenticationException())
+        );
+        $this->assertEquals(
+            RestUtils::UNKNOWN_ERROR,
+            RestUtils::getRestErrorCodeFromException(new WrongIpException())
+        );
+    }
+}
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index 06e1e939..ddd4f42b 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -20,6 +20,10 @@
             <directory suffix=".php">./module/Core/src</directory>
             <directory suffix=".php">./module/Rest/src</directory>
             <directory suffix=".php">./module/CLI/src</directory>
+
+            <exclude>
+                <directory suffix=".php">./module/Core/src/Repository</directory>
+            </exclude>
         </whitelist>
     </filter>
 </phpunit>