diff --git a/README.md b/README.md
index 07671aa..6dcd251 100644
--- a/README.md
+++ b/README.md
@@ -29,11 +29,18 @@ you'd like to install with your library:
         "dependency": [
             "package/to-require",
             ...
-        ]
+        ],
+        "dependency-or": {
+            "Question": [
+                "package/to-choose",
+                "package/or-this",
+                ...
+            ]
+        }
     },
     "require": {
         "php": "^5.6 || ^7.0",
-        "webimpress/composer-extra-dependency": "^0.1 || ^1.0",
+        "webimpress/composer-extra-dependency": "^0.3 || ^1.0",
         ...
     }
     ...  
diff --git a/src/Plugin.php b/src/Plugin.php
index e8c31b1..b020657 100644
--- a/src/Plugin.php
+++ b/src/Plugin.php
@@ -21,6 +21,9 @@
 use Composer\Repository\CompositeRepository;
 use Composer\Repository\PlatformRepository;
 use Composer\Repository\RepositoryFactory;
+use Composer\Script\Event;
+use InvalidArgumentException;
+use RuntimeException;
 
 class Plugin implements PluginInterface, EventSubscriberInterface
 {
@@ -48,11 +51,16 @@ class Plugin implements PluginInterface, EventSubscriberInterface
     /** @var CompositeRepository */
     private $repos;
 
+    /** @var string[] */
+    private $packagesToInstall = [];
+
     public static function getSubscribedEvents()
     {
         return [
             'post-package-install' => 'onPostPackage',
             'post-package-update'  => 'onPostPackage',
+            'post-install-cmd' => 'onPostCommand',
+            'post-update-cmd'  => 'onPostCommand',
         ];
     }
 
@@ -63,7 +71,27 @@ public function activate(Composer $composer, IOInterface $io)
 
         $installedPackages = $this->composer->getRepositoryManager()->getLocalRepository()->getPackages();
         foreach ($installedPackages as $package) {
-            $this->installedPackages[$package->getName()] = $package->getPrettyVersion();
+            $this->installedPackages[strtolower($package->getName())] = $package->getPrettyVersion();
+        }
+    }
+
+    public function onPostCommand(Event $event)
+    {
+        if (! $event->isDevMode()) {
+            // Do nothing in production mode.
+            return;
+        }
+
+        if (! $this->io->isInteractive()) {
+            // Do nothing in no-interactive mode
+            return;
+        }
+
+        if ($this->packagesToInstall) {
+            $this->updateComposerJson($this->packagesToInstall);
+
+            $rootPackage = $this->updateRootPackage($this->composer->getPackage(), $this->packagesToInstall);
+            $this->runInstaller($rootPackage, array_keys($this->packagesToInstall));
         }
     }
 
@@ -85,36 +113,89 @@ public function onPostPackage(PackageEvent $event)
         } else {
             $package = $operation->getTargetPackage();
         }
-        $extra = $this->getExtraMetadata($package->getExtra());
-        if (empty($extra)) {
-            // Package does not define anything of interest; do nothing.
-            return;
+
+        $extra = $package->getExtra();
+
+        $this->packagesToInstall += $this->andDependencies($extra);
+        $this->packagesToInstall += $this->orDependencies($extra);
+    }
+
+    private function andDependencies(array $extra)
+    {
+        $deps = isset($extra['dependency']) && is_array($extra['dependency'])
+            ? $extra['dependency']
+            : [];
+
+        if (! $deps) {
+            // No defined any packages to install
+            return [];
         }
 
-        $packages = array_flip($extra);
+        $packages = array_flip($deps);
 
         foreach ($packages as $package => &$constraint) {
+            if ($this->isPackageReadyToInstall($package)) {
+                unset($packages[$package]);
+                continue;
+            }
+
             if ($this->hasPackage($package)) {
                 unset($packages[$package]);
                 continue;
             }
 
+            // Check if package is currently installed and use installed version.
+            if ($constraint = $this->getInstalledPackageConstraint($package)) {
+                continue;
+            }
+
+            // Package is not installed, then prompt user for the version.
             $constraint = $this->promptForPackageVersion($package);
         }
 
-        if ($packages) {
-            $this->updateComposerJson($packages);
-
-            $rootPackage = $this->updateRootPackage($this->composer->getPackage(), $packages);
-            $this->runInstaller($rootPackage, array_keys($packages));
-        }
+        return $packages;
     }
 
-    private function getExtraMetadata(array $extra)
+    private function orDependencies(array $extra)
     {
-        return isset($extra['dependency']) && is_array($extra['dependency'])
-            ? $extra['dependency']
+        $deps = isset($extra['dependency-or']) && is_array($extra['dependency-or'])
+            ? $extra['dependency-or']
             : [];
+
+        if (! $deps) {
+            // No any dependencies to choose defined in the package.
+            return [];
+        }
+
+        $packages = [];
+        foreach ($deps as $question => $options) {
+            if (! is_array($options) || count($options) < 2) {
+                throw new RuntimeException('You must provide at least two optional dependencies.');
+            }
+
+            foreach ($options as $package) {
+                if ($this->isPackageReadyToInstall($package)) {
+                    // Package has been already prepared to be installed, skipping.
+                    continue 2;
+                }
+
+                if ($this->hasPackage($package)) {
+                    // Package from this group has been found in root composer, skipping.
+                    continue 2;
+                }
+
+                // Check if package is currently installed, if so, use installed constraint and skip question.
+                if ($constraint = $this->getInstalledPackageConstraint($package)) {
+                    $packages[$package] = $constraint;
+                    continue 2;
+                }
+            }
+
+            $package = $this->promptForPackageSelection($question, $options);
+            $packages[$package] = $this->promptForPackageVersion($package);
+        }
+
+        return $packages;
     }
 
     private function updateRootPackage(RootPackageInterface $rootPackage, array $packages)
@@ -157,21 +238,55 @@ private function runInstaller(RootPackageInterface $rootPackage, array $packages
         return $installer->run();
     }
 
-    private function promptForPackageVersion($name)
+    private function getInstalledPackageConstraint($package)
     {
+        $lower = strtolower($package);
+
         // Package is currently installed. Add it to root composer.json
-        if (isset($this->installedPackages[$name])) {
-            $this->io->write(sprintf(
-                'Added package <info>%s</info> to composer.json with constraint <info>%s</info>;'
-                    . ' to upgrade, run <info>composer require %s:VERSION</info>',
-                $name,
-                '^' . $this->installedPackages[$name],
-                $name
-            ));
+        if (! isset($this->installedPackages[$lower])) {
+            return null;
+        }
+
+        $constraint = '^' . $this->installedPackages[$lower];
+        $this->io->write(sprintf(
+            'Added package <info>%s</info> to composer.json with constraint <info>%s</info>;'
+            . ' to upgrade, run <info>composer require %s:VERSION</info>',
+            $package,
+            $constraint,
+            $package
+        ));
+
+        return $constraint;
+    }
 
-            return '^' . $this->installedPackages[$name];
+    private function promptForPackageSelection($question, array $packages)
+    {
+        $ask = [sprintf('<question>%s</question>' . "\n", $question)];
+        foreach ($packages as $i => $name) {
+            $ask[] = sprintf('  [<comment>%d</comment>] %s' . "\n", $i + 1, $name);
         }
+        $ask[] = '  Make your selection: ';
+
+        do {
+            $package = $this->io->askAndValidate(
+                $ask,
+                function ($input) use ($packages) {
+                    $input = is_numeric($input) ? (int) trim($input) : 0;
+
+                    if (isset($packages[$input - 1])) {
+                        return $packages[$input - 1];
+                    }
+
+                    return null;
+                }
+            );
+        } while (! $package);
 
+        return $package;
+    }
+
+    private function promptForPackageVersion($name)
+    {
         $constraint = $this->io->askAndValidate(
             sprintf(
                 'Enter the version of <info>%s</info> to require (or leave blank to use the latest version): ',
@@ -214,10 +329,25 @@ private function createInstaller(Composer $composer, IOInterface $io, RootPackag
 
     private function hasPackage($package)
     {
+        $lower = strtolower($package);
+
         $rootPackage = $this->composer->getPackage();
         $requires = $rootPackage->getRequires() + $rootPackage->getDevRequires();
         foreach ($requires as $name => $link) {
-            if (strtolower($name) === strtolower($package)) {
+            if (strtolower($name) === $lower) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    private function isPackageReadyToInstall($package)
+    {
+        $lower = strtolower($package);
+
+        foreach ($this->packagesToInstall as $name => $version) {
+            if (strtolower($name) === $lower) {
                 return true;
             }
         }
@@ -282,7 +412,7 @@ private function findBestVersionForPackage($name)
         $package = $versionSelector->findBestCandidate($name, null, null, 'stable');
 
         if (! $package) {
-            throw new \InvalidArgumentException(sprintf(
+            throw new InvalidArgumentException(sprintf(
                 'Could not find package %s at any version for your minimum-stability (%s).'
                     . ' Check the package spelling or your minimum-stability',
                 $name,
diff --git a/test/PluginTest.php b/test/PluginTest.php
index fff6b98..e10ee58 100644
--- a/test/PluginTest.php
+++ b/test/PluginTest.php
@@ -19,12 +19,15 @@
 use Composer\Package\Version\VersionSelector;
 use Composer\Repository\RepositoryManager;
 use Composer\Repository\WritableRepositoryInterface;
+use Composer\Script\Event;
 use org\bovigo\vfs\vfsStream;
+use PHPUnit\Framework\Assert;
 use PHPUnit\Framework\TestCase;
 use Prophecy\Argument;
 use Prophecy\Prophecy\ObjectProphecy;
 use ReflectionMethod;
 use ReflectionProperty;
+use RuntimeException;
 use Webimpress\ComposerExtraDependency\Plugin;
 
 class PluginTest extends TestCase
@@ -62,7 +65,24 @@ protected function setUp()
         $this->plugin->activate($this->composer->reveal(), $this->io->reveal());
     }
 
-    protected function setUpComposerInstaller(array $expectedPackages, $expectedReturn = 0)
+    private function setUpRootPackage(
+        array $dependencies = [],
+        array $devDependencies = [],
+        $minimumStability = null
+    ) {
+        $rootPackage = $this->prophesize(RootPackageInterface::class);
+        $rootPackage->getRequires()->willReturn($dependencies)->shouldBeCalled();
+        $rootPackage->getDevRequires()->willReturn($devDependencies)->shouldBeCalled();
+        if ($minimumStability) {
+            $rootPackage->getMinimumStability()->willReturn($minimumStability)->shouldBeCalled();
+        } else {
+            $rootPackage->getMinimumStability()->shouldNotBeCalled();
+        }
+
+        $this->composer->getPackage()->willReturn($rootPackage->reveal())->shouldBeCalled();
+    }
+
+    private function setUpComposerInstaller(array $expectedPackages, $expectedReturn = 0)
     {
         $installer = $this->prophesize(Installer::class);
         $installer->setRunScripts(false)->shouldBeCalled();
@@ -78,7 +98,7 @@ protected function setUpComposerInstaller(array $expectedPackages, $expectedRetu
         });
     }
 
-    protected function setUpVersionSelector(VersionSelector $versionSelector)
+    private function setUpVersionSelector(VersionSelector $versionSelector)
     {
         $r = new ReflectionProperty($this->plugin, 'versionSelectorFactory');
         $r->setAccessible(true);
@@ -87,7 +107,7 @@ protected function setUpVersionSelector(VersionSelector $versionSelector)
         });
     }
 
-    protected function setUpPool()
+    private function setUpPool()
     {
         $pool = $this->prophesize(Pool::class);
 
@@ -96,7 +116,7 @@ protected function setUpPool()
         $r->setValue($this->plugin, $pool->reveal());
     }
 
-    protected function setUpComposerJson($data = null)
+    private function setUpComposerJson($data = null)
     {
         $project = vfsStream::setup('project');
         vfsStream::newFile('composer.json')
@@ -110,13 +130,13 @@ protected function setUpComposerJson($data = null)
         });
     }
 
-    protected function createComposerJson($data)
+    private function createComposerJson($data)
     {
         $data = $data ?: $this->getDefaultComposerData();
         return json_encode($data);
     }
 
-    protected function getDefaultComposerData()
+    private function getDefaultComposerData()
     {
         return [
             'name' => 'test/project',
@@ -128,6 +148,46 @@ protected function getDefaultComposerData()
         ];
     }
 
+    private function getCommandEvent($isDevMode = true)
+    {
+        $event = $this->prophesize(Event::class);
+        $event->isDevMode()->willReturn($isDevMode);
+
+        return $event->reveal();
+    }
+
+    private function getPackageEvent(
+        $packageName,
+        array $extra,
+        $operationClass = InstallOperation::class
+    ) {
+        /** @var PackageInterface|ObjectProphecy $package */
+        $package = $this->prophesize(PackageInterface::class);
+        $package->getName()->willReturn($packageName);
+        $package->getExtra()->willReturn($extra);
+
+        $operation = $this->prophesize($operationClass);
+        if ($operationClass === InstallOperation::class) {
+            $operation->getPackage()->willReturn($package->reveal());
+        } else {
+            $operation->getTargetPackage()->willReturn($package->reveal());
+        }
+
+        $event = $this->prophesize(PackageEvent::class);
+        $event->isDevMode()->willReturn(true);
+        $event->getOperation()->willReturn($operation->reveal())->shouldBeCalled();
+
+        return $event->reveal();
+    }
+
+    private function injectPackages(array $packagesToInstall)
+    {
+        $p = new ReflectionProperty($this->plugin, 'packagesToInstall');
+        $p->setAccessible(true);
+
+        $p->setValue($this->plugin, $packagesToInstall);
+    }
+
     public function testActivateSetsComposerAndIoProperties()
     {
         $plugin = new Plugin();
@@ -142,111 +202,162 @@ public function testSubscribesToExpectedEvents()
         $subscribers = Plugin::getSubscribedEvents();
         $this->assertArrayHasKey('post-package-install', $subscribers);
         $this->assertArrayHasKey('post-package-update', $subscribers);
+        $this->assertArrayHasKey('post-install-cmd', $subscribers);
+        $this->assertArrayHasKey('post-update-cmd', $subscribers);
 
         $this->assertEquals('onPostPackage', $subscribers['post-package-install']);
         $this->assertEquals('onPostPackage', $subscribers['post-package-update']);
+        $this->assertEquals('onPostCommand', $subscribers['post-install-cmd']);
+        $this->assertEquals('onPostCommand', $subscribers['post-update-cmd']);
     }
 
-    public function testDoNothingIfItIsNotInDevMode()
+    public function testPostPackageDoNothingInNoDevMode()
     {
         $event = $this->prophesize(PackageEvent::class);
         $event->isDevMode()->willReturn(false);
+        $event->getOperation()->shouldNotBeCalled();
 
         $this->assertNull($this->plugin->onPostPackage($event->reveal()));
     }
 
-    public function testDoNothingInNoInteractionMode()
+    public function testPostCommandDoNothingInNoDevMode()
     {
-        /** @var PackageInterface|ObjectProphecy $package */
-        $package = $this->prophesize(PackageInterface::class);
-        $package->getName()->willReturn('some/component');
-        $package->getExtra()->willReturn([
-            'dependency' => [
-                'extra-dependency-foo',
-            ],
-        ]);
-
-        $operation = $this->prophesize(InstallOperation::class);
-        $operation->getPackage()->willReturn($package->reveal());
+        $this->assertNull($this->plugin->onPostCommand($this->getCommandEvent(false)));
+    }
 
+    public function testPostPackageDoNothingInNoInteractionMode()
+    {
         $event = $this->prophesize(PackageEvent::class);
         $event->isDevMode()->willReturn(true);
-        $event->getOperation()->willReturn($operation->reveal());
-
-        $rootPackage = $this->prophesize(RootPackageInterface::class);
-        $rootPackage->getRequires()->willReturn([]);
-        $rootPackage->getDevRequires()->willReturn([]);
-
-        $this->composer->getPackage()->willReturn($rootPackage);
+        $event->getOperation()->shouldNotBeCalled();
 
         $this->io->isInteractive()->willReturn(false);
 
         $this->assertNull($this->plugin->onPostPackage($event->reveal()));
     }
 
-    public function testDoNothingWhenThereIsNoExtraDependencies()
+    public function testPostCommandDoNothingInNoInteractionMode()
     {
-        /** @var PackageInterface|ObjectProphecy $package */
-        $package = $this->prophesize(PackageInterface::class);
-        $package->getName()->willReturn('some/component');
-        $package->getExtra()->willReturn([]);
-
-        $operation = $this->prophesize(InstallOperation::class);
-        $operation->getPackage()->willReturn($package->reveal());
+        $this->injectPackages([
+            'my-package-foo' => '2.37.1',
+            'other-package' => 'dev-feature/branch',
+        ]);
 
-        $event = $this->prophesize(PackageEvent::class);
-        $event->isDevMode()->willReturn(true);
-        $event->getOperation()->willReturn($operation->reveal());
+        $this->io->isInteractive()->willReturn(false);
 
-        $this->assertNull($this->plugin->onPostPackage($event->reveal()));
+        $this->assertNull($this->plugin->onPostCommand($this->getCommandEvent()));
     }
 
-    public function testDependencyAlreadyIsInRequiredSection()
+    public function sortPackages()
     {
-        /** @var PackageInterface|ObjectProphecy $package */
-        $package = $this->prophesize(PackageInterface::class);
-        $package->getName()->willReturn('some/component');
-        $package->getExtra()->willReturn([
-            'dependency' => [
-                'extra-dependency-foo',
+        return [
+            [
+                true,
+                [
+                    'zoo/bar' => '1.2.4',
+                    'foo/baz' => '2.7.3',
+                ],
+                '{"foo\/baz":"2.7.3","webimpress\/my-package":"^1.0.0-dev@dev","zoo\/bar":"1.2.4"}',
             ],
-        ]);
+            [
+                false,
+                [
+                    'zoo/bar' => '1.2.4',
+                    'foo/baz' => '2.7.3',
+                ],
+                '{"webimpress\/my-package":"^1.0.0-dev@dev","zoo\/bar":"1.2.4","foo\/baz":"2.7.3"}',
+            ],
+        ];
+    }
 
-        $operation = $this->prophesize(InstallOperation::class);
-        $operation->getPackage()->willReturn($package->reveal());
+    /**
+     * @dataProvider sortPackages
+     *
+     * @param bool $sortPackages
+     * @param array $packages
+     * @param string $result
+     */
+    public function testPostCommandInstallPackagesAndUpdateComposer($sortPackages, array $packages, $result)
+    {
+        $this->injectPackages($packages);
 
-        $event = $this->prophesize(PackageEvent::class);
-        $event->isDevMode()->willReturn(true);
-        $event->getOperation()->willReturn($operation->reveal());
+        $this->io->isInteractive()->willReturn(true);
+        $this->io->write('<info>    Updating composer.json</info>')->shouldBeCalled();
+        $this->io->write('<info>Updating root package</info>')->shouldBeCalled();
+        $this->io->write('<info>    Running an update to install dependent packages</info>')->shouldBeCalled();
 
-        $link = $this->prophesize(Link::class);
-        $link->getTarget()->willReturn('extra-dependency-foo');
+        $config = $this->prophesize(Config::class);
+        $config->get('sort-packages')->willReturn($sortPackages)->shouldBeCalled();
 
         $rootPackage = $this->prophesize(RootPackageInterface::class);
-        $rootPackage->getDevRequires()->willReturn(['extra-dependency-foo' => $link->reveal()]);
+        $rootPackage->getRequires()->willReturn([])->shouldBeCalled();
+        $rootPackage->getDevRequires()->willReturn([])->shouldNotBeCalled();
+        $rootPackage->setRequires(Argument::that(function (array $arguments) use ($packages) {
+            if (count($arguments) !== count($packages)) {
+                return false;
+            }
 
-        $this->composer->getPackage()->willReturn($rootPackage);
+            foreach ($packages as $package => $version) {
+                if (! $this->assertSetRequiresArgument($package, $version, $arguments)) {
+                    return false;
+                }
+            }
 
-        $this->assertNull($this->plugin->onPostPackage($event->reveal()));
+            return true;
+        }))->shouldBeCalled();
+
+        $this->composer->getPackage()->willReturn($rootPackage)->shouldBeCalled();
+        $this->composer->getConfig()->willReturn($config->reveal())->shouldBeCalled();
+
+        $this->setUpComposerJson();
+        $this->setUpComposerInstaller(array_keys($packages));
+
+        $this->assertNull($this->plugin->onPostCommand($this->getCommandEvent()));
+
+        $json = file_get_contents(vfsStream::url('project/composer.json'));
+        $composer = json_decode($json, true);
+        foreach ($packages as $package => $version) {
+            $this->assertTrue(isset($composer['require'][$package]));
+            $this->assertSame($version, $composer['require'][$package]);
+        }
+        $this->assertSame($result, json_encode($composer['require']));
     }
 
-    public function testDependencyAlreadyIsInRequiredDevSection()
+    public function operation()
     {
-        /** @var PackageInterface|ObjectProphecy $package */
-        $package = $this->prophesize(PackageInterface::class);
-        $package->getName()->willReturn('some/component');
-        $package->getExtra()->willReturn([
+        return [
+            'install' => [InstallOperation::class],
+            'update' => [UpdateOperation::class],
+        ];
+    }
+
+    /**
+     * @dataProvider operation
+     *
+     * @param string $operation
+     */
+    public function testDoNothingWhenThereIsNoExtraDependencies($operation)
+    {
+        $event = $this->getPackageEvent('some/component', [], $operation);
+
+        $this->io->isInteractive()->willReturn(true)->shouldBeCalled();
+
+        $this->assertNull($this->plugin->onPostPackage($event));
+        $this->assertPackagesToInstall([]);
+    }
+
+    /**
+     * @dataProvider operation
+     *
+     * @param string $operation
+     */
+    public function testDependencyAlreadyIsInRequireSection($operation)
+    {
+        $event = $this->getPackageEvent('some/component', [
             'dependency' => [
                 'extra-dependency-foo',
             ],
-        ]);
-
-        $operation = $this->prophesize(InstallOperation::class);
-        $operation->getPackage()->willReturn($package->reveal());
-
-        $event = $this->prophesize(PackageEvent::class);
-        $event->isDevMode()->willReturn(true);
-        $event->getOperation()->willReturn($operation->reveal());
+        ], $operation);
 
         $this->io->isInteractive()->willReturn(true)->shouldBeCalled();
         $this->io->askAndValidate(Argument::any())->shouldNotBeCalled();
@@ -255,109 +366,59 @@ public function testDependencyAlreadyIsInRequiredDevSection()
         $link->getTarget()->willReturn('extra-dependency-foo');
 
         $rootPackage = $this->prophesize(RootPackageInterface::class);
-        $rootPackage->getRequires()->willReturn([]);
-        $rootPackage->getDevRequires()->willReturn(['extra-dependency-foo' => $link->reveal()]);
+        $rootPackage->getRequires()->willReturn(['extra-dependency-foo' => $link->reveal()])->shouldBeCalled();
+        $rootPackage->getDevRequires()->willReturn([])->shouldBeCalled();
 
         $this->composer->getPackage()->willReturn($rootPackage);
 
-        $this->assertNull($this->plugin->onPostPackage($event->reveal()));
+        $this->assertNull($this->plugin->onPostPackage($event));
+        $this->assertPackagesToInstall([]);
     }
 
-    public function testInstallSingleDependencyOnPackageUpdate()
+    /**
+     * @dataProvider operation
+     *
+     * @param string $operation
+     */
+    public function testDependencyAlreadyIsInRequireDevSection($operation)
     {
-        /** @var PackageInterface|ObjectProphecy $package */
-        $package = $this->prophesize(PackageInterface::class);
-        $package->getName()->willReturn('some/component');
-        $package->getExtra()->willReturn([
+        $event = $this->getPackageEvent('some/component', [
             'dependency' => [
                 'extra-dependency-foo',
             ],
-        ]);
-
-        $operation = $this->prophesize(UpdateOperation::class);
-        $operation->getTargetPackage()->willReturn($package->reveal());
-
-        $event = $this->prophesize(PackageEvent::class);
-        $event->isDevMode()->willReturn(true);
-        $event->getOperation()->willReturn($operation->reveal());
+        ], $operation);
 
         $this->io->isInteractive()->willReturn(true)->shouldBeCalled();
         $this->io->askAndValidate(Argument::any())->shouldNotBeCalled();
 
-        $config = $this->prophesize(Config::class);
-        $config->get('sort-packages')->willReturn(true);
-        $config->get(Argument::any())->willReturn(null);
+        $link = $this->prophesize(Link::class);
+        $link->getTarget()->willReturn('extra-dependency-foo');
 
         $rootPackage = $this->prophesize(RootPackageInterface::class);
         $rootPackage->getRequires()->willReturn([]);
-        $rootPackage->getDevRequires()->willReturn([]);
-        $rootPackage->setRequires(Argument::that(function ($arguments) {
-            if (! is_array($arguments)) {
-                return false;
-            }
-
-            if (! isset($arguments['extra-dependency-foo'])) {
-                return false;
-            }
-
-            $argument = $arguments['extra-dependency-foo'];
-
-            if (! $argument instanceof Link) {
-                return false;
-            }
-
-            if ($argument->getTarget() !== 'extra-dependency-foo') {
-                return false;
-            }
-
-            if ($argument->getConstraint()->getPrettyString() !== '17.0.1-dev') {
-                return false;
-            }
-
-            if ($argument->getDescription() !== 'requires') {
-                return false;
-            }
-
-            return true;
-        }))->shouldBeCalled();
+        $rootPackage->getDevRequires()->willReturn(['extra-dependency-foo' => $link->reveal()]);
 
         $this->composer->getPackage()->willReturn($rootPackage);
-        $this->composer->getConfig()->willReturn($config->reveal());
 
-        $this->io->isInteractive()->willReturn(true);
-        $this->io->askAndValidate(
-            'Enter the version of <info>extra-dependency-foo</info> to require'
-                . ' (or leave blank to use the latest version): ',
-            Argument::type('callable')
-        )->willReturn('17.0.1-dev');
-
-        $this->io->write('<info>    Updating composer.json</info>')->shouldBeCalled();
-        $this->io->write('<info>Updating root package</info>')->shouldBeCalled();
-        $this->io->write('<info>    Running an update to install dependent packages</info>')->shouldBeCalled();
-
-        $this->setUpComposerInstaller(['extra-dependency-foo']);
-        $this->setUpComposerJson();
-
-        $this->assertNull($this->plugin->onPostPackage($event->reveal()));
+        $this->assertNull($this->plugin->onPostPackage($event));
+        $this->assertPackagesToInstall([]);
     }
 
-    public function testInstallSingleDependencyOnPackageInstall()
+    /**
+     * @dataProvider operation
+     *
+     * @param string $operation
+     */
+    public function testInstallSingleDependency($operation)
     {
-        /** @var PackageInterface|ObjectProphecy $package */
-        $package = $this->prophesize(PackageInterface::class);
-        $package->getName()->willReturn('some/component');
-        $package->getExtra()->willReturn([
+        $event = $this->getPackageEvent('some/component', [
             'dependency' => [
                 'extra-dependency-foo',
             ],
-        ]);
-
-        $operation = $this->prophesize(InstallOperation::class);
-        $operation->getPackage()->willReturn($package->reveal());
+        ], $operation);
 
-        $event = $this->prophesize(PackageEvent::class);
-        $event->isDevMode()->willReturn(true);
-        $event->getOperation()->willReturn($operation->reveal());
+        $this->io->isInteractive()->willReturn(true)->shouldBeCalled();
+        $this->io->askAndValidate(Argument::any())->shouldNotBeCalled();
 
         $config = $this->prophesize(Config::class);
         $config->get('sort-packages')->willReturn(true);
@@ -366,35 +427,6 @@ public function testInstallSingleDependencyOnPackageInstall()
         $rootPackage = $this->prophesize(RootPackageInterface::class);
         $rootPackage->getRequires()->willReturn([]);
         $rootPackage->getDevRequires()->willReturn([]);
-        $rootPackage->setRequires(Argument::that(function ($arguments) {
-            if (! is_array($arguments)) {
-                return false;
-            }
-
-            if (! isset($arguments['extra-dependency-foo'])) {
-                return false;
-            }
-
-            $argument = $arguments['extra-dependency-foo'];
-
-            if (! $argument instanceof Link) {
-                return false;
-            }
-
-            if ($argument->getTarget() !== 'extra-dependency-foo') {
-                return false;
-            }
-
-            if ($argument->getConstraint()->getPrettyString() !== '17.0.1-dev') {
-                return false;
-            }
-
-            if ($argument->getDescription() !== 'requires') {
-                return false;
-            }
-
-            return true;
-        }))->shouldBeCalled();
 
         $this->composer->getPackage()->willReturn($rootPackage);
         $this->composer->getConfig()->willReturn($config->reveal());
@@ -403,37 +435,40 @@ public function testInstallSingleDependencyOnPackageInstall()
         $this->io->askAndValidate(
             'Enter the version of <info>extra-dependency-foo</info> to require'
                 . ' (or leave blank to use the latest version): ',
-            Argument::type('callable')
+            Argument::that(function ($arg) {
+                if (! is_callable($arg)) {
+                    return false;
+                }
+
+                Assert::assertFalse($arg(0));
+                Assert::assertFalse($arg('0'));
+                Assert::assertFalse($arg(''));
+                Assert::assertFalse($arg(' '));
+                Assert::assertSame('1', $arg('  1 '));
+                Assert::assertSame('1', $arg('1'));
+                Assert::assertSame('0.*', $arg('0.*'));
+
+                return true;
+            })
         )->willReturn('17.0.1-dev');
 
-        $this->io->write('<info>    Updating composer.json</info>')->shouldBeCalled();
-        $this->io->write('<info>Updating root package</info>')->shouldBeCalled();
-        $this->io->write('<info>    Running an update to install dependent packages</info>')->shouldBeCalled();
-
-        $this->setUpComposerInstaller(['extra-dependency-foo']);
-        $this->setUpComposerJson();
-
-        $this->assertNull($this->plugin->onPostPackage($event->reveal()));
+        $this->assertNull($this->plugin->onPostPackage($event));
+        $this->assertPackagesToInstall(['extra-dependency-foo' => '17.0.1-dev']);
     }
 
-    public function testInstallOneDependenciesWhenOneIsAlreadyInstalled()
+    /**
+     * @dataProvider operation
+     *
+     * @param string $operation
+     */
+    public function testInstallOneDependenciesWhenOneIsAlreadyInstalled($operation)
     {
-        /** @var PackageInterface|ObjectProphecy $package */
-        $package = $this->prophesize(PackageInterface::class);
-        $package->getName()->willReturn('some/component');
-        $package->getExtra()->willReturn([
+        $event = $this->getPackageEvent('some/component', [
             'dependency' => [
                 'extra-dependency-foo',
                 'extra-dependency-bar',
             ],
-        ]);
-
-        $operation = $this->prophesize(InstallOperation::class);
-        $operation->getPackage()->willReturn($package->reveal());
-
-        $event = $this->prophesize(PackageEvent::class);
-        $event->isDevMode()->willReturn(true);
-        $event->getOperation()->willReturn($operation->reveal());
+        ], $operation);
 
         $config = $this->prophesize(Config::class);
         $config->get('sort-packages')->willReturn(true);
@@ -445,39 +480,6 @@ public function testInstallOneDependenciesWhenOneIsAlreadyInstalled()
         $rootPackage = $this->prophesize(RootPackageInterface::class);
         $rootPackage->getRequires()->willReturn(['extra-dependency-bar' => $link->reveal()]);
         $rootPackage->getDevRequires()->willReturn([]);
-        $rootPackage->setRequires(Argument::that(function ($arguments) {
-            if (! is_array($arguments)) {
-                return false;
-            }
-
-            if (! isset($arguments['extra-dependency-foo'])) {
-                return false;
-            }
-
-            if (! isset($arguments['extra-dependency-bar'])) {
-                return false;
-            }
-
-            $argument = $arguments['extra-dependency-foo'];
-
-            if (! $argument instanceof Link) {
-                return false;
-            }
-
-            if ($argument->getTarget() !== 'extra-dependency-foo') {
-                return false;
-            }
-
-            if ($argument->getConstraint()->getPrettyString() !== '17.0.1-dev') {
-                return false;
-            }
-
-            if ($argument->getDescription() !== 'requires') {
-                return false;
-            }
-
-            return true;
-        }))->shouldBeCalled();
 
         $this->composer->getPackage()->willReturn($rootPackage);
         $this->composer->getConfig()->willReturn($config->reveal());
@@ -489,79 +491,24 @@ public function testInstallOneDependenciesWhenOneIsAlreadyInstalled()
             Argument::type('callable')
         )->willReturn('17.0.1-dev');
 
-        $this->io->write('<info>    Updating composer.json</info>')->shouldBeCalled();
-        $this->io->write('<info>Updating root package</info>')->shouldBeCalled();
-        $this->io->write('<info>    Running an update to install dependent packages</info>')->shouldBeCalled();
-
-        $this->setUpComposerInstaller(['extra-dependency-foo']);
-        $this->setUpComposerJson();
-
-        $this->assertNull($this->plugin->onPostPackage($event->reveal()));
-
-        $json = file_get_contents(vfsStream::url('project/composer.json'));
-        $composer = json_decode($json, true);
-        $this->assertTrue(isset($composer['require']['extra-dependency-foo']));
-        $this->assertSame('17.0.1-dev', $composer['require']['extra-dependency-foo']);
+        $this->assertNull($this->plugin->onPostPackage($event));
+        $this->assertPackagesToInstall(['extra-dependency-foo' => '17.0.1-dev']);
     }
 
-    public function testInstallSingleDependencyAndAutomaticallyChooseLatestVersion()
+    /**
+     * @dataProvider operation
+     *
+     * @param string $operation
+     */
+    public function testInstallSingleDependencyAndAutomaticallyChooseLatestVersion($operation)
     {
-        /** @var PackageInterface|ObjectProphecy $package */
-        $package = $this->prophesize(PackageInterface::class);
-        $package->getName()->willReturn('some/component');
-        $package->getExtra()->willReturn([
+        $event = $this->getPackageEvent('some/component', [
             'dependency' => [
                 'extra-dependency-foo',
             ],
-        ]);
-
-        $operation = $this->prophesize(InstallOperation::class);
-        $operation->getPackage()->willReturn($package->reveal());
-
-        $event = $this->prophesize(PackageEvent::class);
-        $event->isDevMode()->willReturn(true);
-        $event->getOperation()->willReturn($operation->reveal());
-
-        $config = $this->prophesize(Config::class);
-        $config->get('sort-packages')->willReturn(true);
-        $config->get(Argument::any())->willReturn(null);
-
-        $rootPackage = $this->prophesize(RootPackageInterface::class);
-        $rootPackage->getRequires()->willReturn([]);
-        $rootPackage->getDevRequires()->willReturn([]);
-        $rootPackage->setRequires(Argument::that(function ($arguments) {
-            if (! is_array($arguments)) {
-                return false;
-            }
-
-            if (! isset($arguments['extra-dependency-foo'])) {
-                return false;
-            }
+        ], $operation);
 
-            $argument = $arguments['extra-dependency-foo'];
-
-            if (! $argument instanceof Link) {
-                return false;
-            }
-
-            if ($argument->getTarget() !== 'extra-dependency-foo') {
-                return false;
-            }
-
-            if ($argument->getConstraint()->getPrettyString() !== '13.4.2') {
-                return false;
-            }
-
-            if ($argument->getDescription() !== 'requires') {
-                return false;
-            }
-
-            return true;
-        }))->shouldBeCalled();
-        $rootPackage->getMinimumStability()->willReturn('stable');
-
-        $this->composer->getPackage()->willReturn($rootPackage);
-        $this->composer->getConfig()->willReturn($config->reveal());
+        $this->setUpRootPackage();
 
         $this->io->isInteractive()->willReturn(true);
         $this->io->askAndValidate(
@@ -570,14 +517,8 @@ public function testInstallSingleDependencyAndAutomaticallyChooseLatestVersion()
             Argument::type('callable')
         )->willReturn(false);
 
-        $this->io->write('<info>    Updating composer.json</info>')->shouldBeCalled();
-        $this->io->write('<info>Updating root package</info>')->shouldBeCalled();
-        $this->io->write('<info>    Running an update to install dependent packages</info>')->shouldBeCalled();
         $this->io->write('Using version <info>13.4.2</info> for <info>extra-dependency-foo</info>')->shouldBeCalled();
 
-        $this->setUpComposerInstaller(['extra-dependency-foo']);
-        $this->setUpComposerJson();
-
         $package = $this->prophesize(PackageInterface::class);
 
         $versionSelector = $this->prophesize(VersionSelector::class);
@@ -591,43 +532,24 @@ public function testInstallSingleDependencyAndAutomaticallyChooseLatestVersion()
         $this->setUpVersionSelector($versionSelector->reveal());
         $this->setUpPool();
 
-        $this->assertNull($this->plugin->onPostPackage($event->reveal()));
-
-        $json = file_get_contents(vfsStream::url('project/composer.json'));
-        $composer = json_decode($json, true);
-        $this->assertTrue(isset($composer['require']['extra-dependency-foo']));
-        $this->assertSame('13.4.2', $composer['require']['extra-dependency-foo']);
+        $this->assertNull($this->plugin->onPostPackage($event));
+        $this->assertPackagesToInstall(['extra-dependency-foo' => '13.4.2']);
     }
 
-    public function testInstallSingleDependencyAndAutomaticallyChooseLatestVersionNotFoundMatchingPackage()
+    /**
+     * @dataProvider operation
+     *
+     * @param string $operation
+     */
+    public function testInstallSingleDependencyAndAutomaticallyChooseLatestVersionNotFoundMatchingPackage($operation)
     {
-        /** @var PackageInterface|ObjectProphecy $package */
-        $package = $this->prophesize(PackageInterface::class);
-        $package->getName()->willReturn('some/component');
-        $package->getExtra()->willReturn([
+        $event = $this->getPackageEvent('some/component', [
             'dependency' => [
                 'extra-dependency-foo',
             ],
-        ]);
+        ], $operation);
 
-        $operation = $this->prophesize(InstallOperation::class);
-        $operation->getPackage()->willReturn($package->reveal());
-
-        $event = $this->prophesize(PackageEvent::class);
-        $event->isDevMode()->willReturn(true);
-        $event->getOperation()->willReturn($operation->reveal());
-
-        $config = $this->prophesize(Config::class);
-        $config->get('sort-packages')->willReturn(true);
-        $config->get(Argument::any())->willReturn(null);
-
-        $rootPackage = $this->prophesize(RootPackageInterface::class);
-        $rootPackage->getRequires()->willReturn([]);
-        $rootPackage->getDevRequires()->willReturn([]);
-        $rootPackage->getMinimumStability()->willReturn('stable');
-
-        $this->composer->getPackage()->willReturn($rootPackage);
-        $this->composer->getConfig()->willReturn($config->reveal());
+        $this->setUpRootPackage([], [], 'stable-foo');
 
         $this->io->isInteractive()->willReturn(true);
         $this->io->askAndValidate(
@@ -636,22 +558,27 @@ public function testInstallSingleDependencyAndAutomaticallyChooseLatestVersionNo
             Argument::type('callable')
         )->willReturn(false);
 
-        $this->setUpComposerJson();
-
         $versionSelector = $this->prophesize(VersionSelector::class);
-        $versionSelector->findBestCandidate('extra-dependency-foo', null, null, 'stable')->willReturn(null);
+        $versionSelector->findBestCandidate('extra-dependency-foo', null, null, 'stable')
+            ->willReturn(null)
+            ->shouldBeCalledTimes(1);
 
         $this->setUpVersionSelector($versionSelector->reveal());
         $this->setUpPool();
 
         $this->expectException(\InvalidArgumentException::class);
         $this->expectExceptionMessage(
-            'Could not find package extra-dependency-foo at any version for your minimum-stability'
+            'Could not find package extra-dependency-foo at any version for your minimum-stability (stable-foo)'
         );
-        $this->plugin->onPostPackage($event->reveal());
+        $this->plugin->onPostPackage($event);
     }
 
-    public function testUpdateComposerWithCurrentlyInstalledVersion()
+    /**
+     * @dataProvider operation
+     *
+     * @param string $operation
+     */
+    public function testUpdateComposerWithCurrentlyInstalledVersion($operation)
     {
         $installedPackage = $this->prophesize(PackageInterface::class);
         $installedPackage->getName()->willReturn('extra-dependency-foo');
@@ -660,83 +587,401 @@ public function testUpdateComposerWithCurrentlyInstalledVersion()
         $this->localRepository->getPackages()->willReturn([$installedPackage->reveal()]);
         $this->plugin->activate($this->composer->reveal(), $this->io->reveal());
 
-        /** @var PackageInterface|ObjectProphecy $package */
-        $package = $this->prophesize(PackageInterface::class);
-        $package->getName()->willReturn('some/component');
-        $package->getExtra()->willReturn([
+        $event = $this->getPackageEvent('some/component', [
             'dependency' => [
                 'extra-dependency-foo',
             ],
+        ], $operation);
+
+        $this->setUpRootPackage();
+
+        $this->io->isInteractive()->willReturn(true);
+        $this->io
+            ->write(
+                'Added package <info>extra-dependency-foo</info> to composer.json with constraint'
+                    . ' <info>^0.5.1</info>; to upgrade, run <info>composer require extra-dependency-foo:VERSION</info>'
+            )
+            ->shouldBeCalled();
+
+        $this->assertNull($this->plugin->onPostPackage($event));
+        $this->assertPackagesToInstall(['extra-dependency-foo' => '^0.5.1']);
+    }
+
+    /**
+     * @dataProvider operation
+     *
+     * @param string $operation
+     */
+    public function testDoNotInstallAskTwiceForTheSamePackage($operation)
+    {
+        $this->injectPackages([
+            'extra-package' => '^1.0.1',
         ]);
 
-        $operation = $this->prophesize(InstallOperation::class);
-        $operation->getPackage()->willReturn($package->reveal());
+        $event = $this->getPackageEvent('some/component', [
+            'dependency' => [
+                'extra-package',
+            ],
+        ], $operation);
 
-        $event = $this->prophesize(PackageEvent::class);
-        $event->isDevMode()->willReturn(true);
-        $event->getOperation()->willReturn($operation->reveal());
+        $this->composer->getPackage()->shouldNotBeCalled();
 
-        $config = $this->prophesize(Config::class);
-        $config->get('sort-packages')->willReturn(true);
-        $config->get(Argument::any())->willReturn(null);
+        $this->io->isInteractive()->willReturn(true);
+        $this->io
+            ->askAndValidate(Argument::any(), Argument::type('callable'))
+            ->shouldNotBeCalled();
 
-        $rootPackage = $this->prophesize(RootPackageInterface::class);
-        $rootPackage->getRequires()->willReturn([]);
-        $rootPackage->getDevRequires()->willReturn([]);
-        $rootPackage->setRequires(Argument::that(function ($arguments) {
-            if (! is_array($arguments)) {
-                return false;
-            }
+        $this->assertNull($this->plugin->onPostPackage($event));
+        $this->assertPackagesToInstall([
+            'extra-package' => '^1.0.1',
+        ]);
+    }
 
-            if (! isset($arguments['extra-dependency-foo'])) {
-                return false;
-            }
+    /**
+     * @dataProvider operation
+     *
+     * @param string $operation
+     */
+    public function testDependencyOrChoosePackageToInstall($operation)
+    {
+        $event = $this->getPackageEvent('some/component', [
+            'dependency-or' => [
+                'My question foo bar baz' => [
+                    'extra-dependency-foo',
+                    'extra-dependency-bar',
+                ],
+            ],
+        ], $operation);
 
-            $argument = $arguments['extra-dependency-foo'];
+        $this->setUpRootPackage();
 
-            if (! $argument instanceof Link) {
-                return false;
-            }
+        $this->io->isInteractive()->willReturn(true);
+        $this->io
+            ->askAndValidate(
+                Argument::that(function ($arg) {
+                    if (! is_array($arg)) {
+                        return false;
+                    }
+
+                    Assert::assertCount(4, $arg);
+                    Assert::assertSame('<question>My question foo bar baz</question>' . "\n", $arg[0]);
+                    Assert::assertSame('  [<comment>1</comment>] extra-dependency-foo' . "\n", $arg[1]);
+                    Assert::assertSame('  [<comment>2</comment>] extra-dependency-bar' . "\n", $arg[2]);
+                    Assert::assertSame('  Make your selection: ', $arg[3]);
+
+                    return true;
+                }),
+                Argument::that(function ($arg) {
+                    if (! is_callable($arg)) {
+                        return false;
+                    }
+
+                    Assert::assertSame('extra-dependency-foo', $arg(1));
+                    Assert::assertSame('extra-dependency-foo', $arg('1'));
+                    Assert::assertSame('extra-dependency-foo', $arg(' 1'));
+                    Assert::assertSame('extra-dependency-foo', $arg('1.0'));
+                    Assert::assertSame('extra-dependency-bar', $arg(2));
+                    Assert::assertSame('extra-dependency-bar', $arg('2'));
+                    Assert::assertSame('extra-dependency-bar', $arg(' 2'));
+                    Assert::assertSame('extra-dependency-bar', $arg('2.2'));
+                    Assert::assertNull($arg(''));
+                    Assert::assertNull($arg(' '));
+                    Assert::assertNull($arg('a'));
+                    Assert::assertNull($arg('1a'));
+                    Assert::assertNull($arg(' a'));
+                    Assert::assertNull($arg(0));
+                    Assert::assertNull($arg(3));
+
+                    return true;
+                })
+            )
+            ->willReturn('', 'extra-dependency-bar')
+            ->shouldBeCalledTimes(2);
+        $this->io
+            ->askAndValidate(
+                'Enter the version of <info>extra-dependency-bar</info> to require'
+                    . ' (or leave blank to use the latest version): ',
+                Argument::type('callable')
+            )
+            ->willReturn(false)
+            ->shouldBeCalledTimes(1);
 
-            if ($argument->getTarget() !== 'extra-dependency-foo') {
-                return false;
-            }
+        $this->io->write('Using version <info>13.4.2</info> for <info>extra-dependency-bar</info>')->shouldBeCalled();
 
-            if ($argument->getConstraint()->getPrettyString() !== '^0.5.1') {
-                return false;
-            }
+        $package = $this->prophesize(PackageInterface::class);
 
-            if ($argument->getDescription() !== 'requires') {
-                return false;
-            }
+        $versionSelector = $this->prophesize(VersionSelector::class);
+        $versionSelector->findBestCandidate('extra-dependency-bar', null, null, 'stable')
+            ->willReturn($package->reveal())
+            ->shouldBeCalled();
+        $versionSelector->findRecommendedRequireVersion($package->reveal())
+            ->willReturn('13.4.2')
+            ->shouldBeCalled();
 
-            return true;
-        }))->shouldBeCalled();
-        $rootPackage->getMinimumStability()->willReturn('stable');
+        $this->setUpVersionSelector($versionSelector->reveal());
+        $this->setUpPool();
 
-        $this->composer->getPackage()->willReturn($rootPackage);
-        $this->composer->getConfig()->willReturn($config->reveal());
+        $this->assertNull($this->plugin->onPostPackage($event));
+        $this->assertPackagesToInstall(['extra-dependency-bar' => '13.4.2']);
+    }
+
+    /**
+     * @dataProvider operation
+     *
+     * @param string $operation
+     */
+    public function testDependencyOrOnePackageIsAlreadyInstalledAndShouldBeAddedIntoRootComposer($operation)
+    {
+        $installedPackage = $this->prophesize(PackageInterface::class);
+        $installedPackage->getName()->willReturn('extra-dependency-baz');
+        $installedPackage->getPrettyVersion()->willReturn('3.7.1');
+
+        $this->localRepository->getPackages()->willReturn([$installedPackage->reveal()]);
+        $this->plugin->activate($this->composer->reveal(), $this->io->reveal());
+
+        $event = $this->getPackageEvent('some/component', [
+            'dependency-or' => [
+                'Choose something' => [
+                    'extra-dependency-bar',
+                    'extra-dependency-baz',
+                ],
+            ],
+        ], $operation);
+
+        $this->setUpRootPackage();
 
         $this->io->isInteractive()->willReturn(true);
         $this->io
             ->write(
-                'Added package <info>extra-dependency-foo</info> to composer.json with constraint'
-                . ' <info>^0.5.1</info>; to upgrade, run <info>composer require extra-dependency-foo:VERSION</info>'
+                'Added package <info>extra-dependency-baz</info> to composer.json with constraint'
+                    . ' <info>^3.7.1</info>; to upgrade, run <info>composer require extra-dependency-baz:VERSION</info>'
             )
             ->shouldBeCalled();
-        $this->io->write('<info>    Updating composer.json</info>')->shouldBeCalled();
-        $this->io->write('<info>Updating root package</info>')->shouldBeCalled();
-        $this->io->write('<info>    Running an update to install dependent packages</info>')->shouldBeCalled();
+        $this->io
+            ->askAndValidate(Argument::any(), Argument::any())
+            ->shouldNotBeCalled();
 
-        $this->setUpComposerInstaller(['extra-dependency-foo']);
-        $this->setUpComposerJson();
+        $this->setUpPool();
 
-        $this->assertNull($this->plugin->onPostPackage($event->reveal()));
+        $this->assertNull($this->plugin->onPostPackage($event));
+        $this->assertPackagesToInstall(['extra-dependency-baz' => '^3.7.1']);
+    }
 
-        $json = file_get_contents(vfsStream::url('project/composer.json'));
-        $composer = json_decode($json, true);
-        $this->assertTrue(isset($composer['require']['extra-dependency-foo']));
-        $this->assertSame('^0.5.1', $composer['require']['extra-dependency-foo']);
+    /**
+     * @dataProvider operation
+     *
+     * @param string $operation
+     */
+    public function testDependencyOrOnePackageIsAlreadyInRootComposer($operation)
+    {
+        $event = $this->getPackageEvent('some/component', [
+            'dependency-or' => [
+                'Choose something' => [
+                    'extra-dependency-foo',
+                    'extra-dependency-baz',
+                ],
+            ],
+        ], $operation);
+
+        $link = $this->prophesize(Link::class);
+        $link->getTarget()->willReturn('extra-dependency-bar');
+
+        $this->setUpRootPackage(['extra-dependency-foo' => $link]);
+
+        $this->io->isInteractive()->willReturn(true)->shouldBeCalledTimes(1);
+        $this->io
+            ->askAndValidate(Argument::any(), Argument::any())
+            ->shouldNotBeCalled();
+
+        $this->assertNull($this->plugin->onPostPackage($event));
+        $this->assertPackagesToInstall([]);
+    }
+
+    /**
+     * @dataProvider operation
+     *
+     * @param string $operation
+     */
+    public function testDependencyOrWrongDefinitionThrowsException($operation)
+    {
+        $event = $this->getPackageEvent('some/component', [
+            'dependency-or' => [
+                'extra-dependency-foo',
+                'extra-dependency-baz',
+            ],
+        ], $operation);
+
+        $this->io->isInteractive()->willReturn(true)->shouldBeCalledTimes(1);
+        $this->io
+            ->askAndValidate(Argument::any(), Argument::any())
+            ->shouldNotBeCalled();
+
+        $this->expectException(RuntimeException::class);
+        $this->expectExceptionMessage('You must provide at least two optional dependencies.');
+        $this->assertNull($this->plugin->onPostPackage($event));
+    }
+
+    /**
+     * @dataProvider operation
+     *
+     * @param string $operation
+     */
+    public function testIntegrationHandleDependencyAndDependencyOr($operation)
+    {
+        $event = $this->getPackageEvent('some/component', [
+            'dependency' => [
+                'extra-package-required',
+            ],
+            'dependency-or' => [
+                'Choose something' => [
+                    'extra-choose-one',
+                    'extra-choose-two',
+                    'extra-choose-three',
+                ],
+            ],
+        ], $operation);
+
+        $this->setUpRootPackage();
+
+        $this->io->isInteractive()->willReturn(true);
+        $this->io
+            ->askAndValidate(
+                Argument::that(function ($arg) {
+                    if (! is_array($arg)) {
+                        return false;
+                    }
+
+                    Assert::assertCount(5, $arg);
+                    Assert::assertSame('<question>Choose something</question>' . "\n", $arg[0]);
+                    Assert::assertSame('  [<comment>1</comment>] extra-choose-one' . "\n", $arg[1]);
+                    Assert::assertSame('  [<comment>2</comment>] extra-choose-two' . "\n", $arg[2]);
+                    Assert::assertSame('  [<comment>3</comment>] extra-choose-three' . "\n", $arg[3]);
+                    Assert::assertSame('  Make your selection: ', $arg[4]);
+
+                    return true;
+                }),
+                Argument::type('callable')
+            )
+            ->willReturn('extra-choose-two')
+            ->shouldBeCalledTimes(1);
+        $this->io
+            ->askAndValidate(
+                'Enter the version of <info>extra-package-required</info> to require'
+                    . ' (or leave blank to use the latest version): ',
+                Argument::type('callable')
+            )
+            ->willReturn(false)
+            ->shouldBeCalledTimes(1);
+        $this->io
+            ->askAndValidate(
+                'Enter the version of <info>extra-choose-two</info> to require'
+                    . ' (or leave blank to use the latest version): ',
+                Argument::type('callable')
+            )
+            ->willReturn(false)
+            ->shouldBeCalledTimes(1);
+
+        $this->io->write('Using version <info>3.9.1</info> for <info>extra-package-required</info>')->shouldBeCalled();
+        $this->io->write('Using version <info>2.1.5</info> for <info>extra-choose-two</info>')->shouldBeCalled();
+
+        $package1 = $this->prophesize(PackageInterface::class)->reveal();
+        $package2 = $this->prophesize(PackageInterface::class)->reveal();
+
+        $versionSelector = $this->prophesize(VersionSelector::class);
+        $versionSelector->findBestCandidate('extra-package-required', null, null, 'stable')
+            ->willReturn($package1)
+            ->shouldBeCalledTimes(1);
+        $versionSelector->findBestCandidate('extra-choose-two', null, null, 'stable')
+            ->willReturn($package2)
+            ->shouldBeCalledTimes(1);
+        $versionSelector->findRecommendedRequireVersion($package1)
+            ->willReturn('3.9.1')
+            ->shouldBeCalledTimes(1);
+        $versionSelector->findRecommendedRequireVersion($package2)
+            ->willReturn('2.1.5')
+            ->shouldBeCalledTimes(1);
+
+        $this->setUpVersionSelector($versionSelector->reveal());
+        $this->setUpPool();
+
+        $this->assertNull($this->plugin->onPostPackage($event));
+        $this->assertPackagesToInstall([
+            'extra-package-required' => '3.9.1',
+            'extra-choose-two' => '2.1.5',
+        ]);
+    }
+
+    /**
+     * @dataProvider operation
+     *
+     * @param string $operation
+     */
+    public function testIntegrationDoNotAskWhenAlreadyChosen($operation)
+    {
+        $event = $this->getPackageEvent('some/component', [
+            'dependency' => [
+                'extra-package-required',
+            ],
+            'dependency-or' => [
+                'Choose something' => [
+                    'extra-choose-one',
+                    'extra-choose-two',
+                    'extra-choose-three',
+                    'extra-package-required',
+                ],
+            ],
+        ], $operation);
+
+        $this->setUpRootPackage();
+
+        $this->io->isInteractive()->willReturn(true);
+        $this->io
+            ->askAndValidate(
+                'Enter the version of <info>extra-package-required</info> to require'
+                . ' (or leave blank to use the latest version): ',
+                Argument::type('callable')
+            )
+            ->willReturn('1.8.3')
+            ->shouldBeCalledTimes(1);
+
+        $this->assertNull($this->plugin->onPostPackage($event));
+        $this->assertPackagesToInstall([
+            'extra-package-required' => '1.8.3',
+        ]);
+    }
+
+    private function assertSetRequiresArgument($name, $version, array $arguments)
+    {
+        if (! isset($arguments[$name])) {
+            return false;
+        }
+
+        $argument = $arguments[$name];
+
+        if (! $argument instanceof Link) {
+            return false;
+        }
+
+        if ($argument->getTarget() !== $name) {
+            return false;
+        }
+
+        if ($argument->getConstraint()->getPrettyString() !== $version) {
+            return false;
+        }
+
+        if ($argument->getDescription() !== 'requires') {
+            return false;
+        }
+
+        return true;
+    }
+
+    private function assertPackagesToInstall(array $packagesToInstall)
+    {
+        $p = new ReflectionProperty($this->plugin, 'packagesToInstall');
+        $p->setAccessible(true);
+        self::assertSame($packagesToInstall, $p->getValue($this->plugin));
     }
 
     public function testComposerInstallerFactory()