diff --git a/.scrutinizer.yml b/.scrutinizer.yml
new file mode 100644
index 0000000..c9de6d6
--- /dev/null
+++ b/.scrutinizer.yml
@@ -0,0 +1,21 @@
+checks:
+  php: true
+
+build:
+  environment:
+    php: 7.4
+  nodes:
+    my-tests:
+      dependencies:
+        before:
+          - cd tests && ./run.sh
+    analysis:
+      tests:
+        override:
+          - php-scrutinizer-run
+
+filter:
+  paths:
+    - "src/*"
+    - "tests/*"
+
diff --git a/.travis.yml b/.travis.yml
index f331730..a8aa171 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,10 +1,9 @@
 language: php
 php:
- - 7.0
- - 7.1
- - 7.2
+ - 7.3
+ - 7.4
 before_script:
-- composer self-update
+- composer self-update --2
 - composer clear-cache
 - composer update
 env:
@@ -18,7 +17,7 @@ script:
 - cd ..; vendor/bin/phpunit
 - "./vendor/bin/phpcs --standard=PSR2 ./src/ ./tests/unitTests --config-set ignore_warnings_on_exit
   1"
-- "./vendor/bin/humbug"
+- "./vendor/bin/infection"
 after_script:
-- php vendor/bin/coveralls -v
+- php vendor/bin/php-coveralls -v
 - "./vendor/bin/couscous travis-auto-deploy --php-version=7.1"
diff --git a/composer.json b/composer.json
index 2e8081f..a059c76 100644
--- a/composer.json
+++ b/composer.json
@@ -13,26 +13,32 @@
         }
     ],
     "require": {
-    	"php": ">=7.0.0",
-        "composer-plugin-api": "^1.0"
+    	"php": ">=7.2",
+        "composer-plugin-api": "^1.0 || ^2.0"
     },
     "require-dev": {
-        "composer/composer": "^1.0",
-        "satooshi/php-coveralls": "^1.0",
-        "phpunit/phpunit": "~5.0",
-        "humbug/humbug": "~1.0",
-        "squizlabs/php_codesniffer": "^2.7.0",
-        "couscous/couscous": "^1.6"
+        "composer/composer": "^1 || ^2",
+        "composer/semver": "^1 || ^2 || ^3",
+        "php-coveralls/php-coveralls": "^2.4.2",
+        "phpunit/phpunit": "^8.5.8",
+        "squizlabs/php_codesniffer": "^2.9.2",
+        "couscous/couscous": "^1.8",
+        "infection/infection": "^0.17.7 || ^1.18.2"
     },
     "autoload": {
         "psr-4": {
             "TheCodingMachine\\Discovery\\": "src/"
         }
     },
+    "autoload-dev": {
+        "psr-4": {
+            "TheCodingMachine\\Discovery\\Tests\\": "tests/unitTests"
+        }
+    },
     "extra": {
         "class": "TheCodingMachine\\Discovery\\DiscoveryPlugin",
         "branch-alias": {
-            "dev-master": "1.1.x-dev"
+            "dev-master": "1.3.x-dev"
         }
     },
     "minimum-stability": "alpha",
diff --git a/infection.json.dist b/infection.json.dist
new file mode 100644
index 0000000..06a97aa
--- /dev/null
+++ b/infection.json.dist
@@ -0,0 +1,16 @@
+{
+  "source": {
+    "directories": [
+      "src"
+    ]
+  },
+  "timeout": 15,
+  "logs": {
+    "text": "infection-log.txt",
+    "summary": "summary-log.txt",
+    "debug": "debug-log.txt"
+  },
+  "phpUnit": {
+      "configDir": "."
+  }
+}
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index 9360f50..179e6f3 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -8,7 +8,6 @@
          convertWarningsToExceptions="true"
          processIsolation="false"
          stopOnFailure="false"
-         syntaxCheck="false"
          bootstrap="vendor/autoload.php"
 >
     <testsuites>
@@ -26,7 +25,7 @@
         </whitelist>
     </filter>
     <logging>
-        <log type="coverage-html" target="build/coverage" charset="UTF-8" yui="true" highlight="true"/>
+        <log type="coverage-html" target="build/coverage"/>
         <log type="coverage-clover" target="build/logs/clover.xml"/>
     </logging>
 </phpunit>
diff --git a/src/AssetsBuilder.php b/src/AssetsBuilder.php
index 139511d..7cda190 100644
--- a/src/AssetsBuilder.php
+++ b/src/AssetsBuilder.php
@@ -116,7 +116,7 @@ private function getDiscoveryJson(PackageInterface $package) : array
 
         $fileSystem = new Filesystem();
 
-        $packageDir = $fileSystem->makePathRelative($packageInstallPath, realpath($this->rootDir));
+        $packageDir = $fileSystem->makePathRelative(realpath($packageInstallPath), realpath($this->rootDir));
 
         $path = $packageInstallPath.'/discovery.json';
 
diff --git a/src/DiscoveryPlugin.php b/src/DiscoveryPlugin.php
index bffc06b..35269e5 100644
--- a/src/DiscoveryPlugin.php
+++ b/src/DiscoveryPlugin.php
@@ -94,4 +94,20 @@ public function getCapabilities()
             CommandProvider::class => DiscoveryCommandProvider::class,
         ];
     }
+
+    /**
+     * @inheritDoc
+     */
+    public function deactivate(Composer $composer, IOInterface $io)
+    {
+
+    }
+
+    /**
+     * @inheritDoc
+     */
+    public function uninstall(Composer $composer, IOInterface $io)
+    {
+
+    }
 }
diff --git a/tests/composer-test.json b/tests/composer-test.json
index 48eca8f..e0eadaf 100644
--- a/tests/composer-test.json
+++ b/tests/composer-test.json
@@ -18,4 +18,4 @@
     "thecodingmachine/discovery": "*",
     "package/b": "*"
   }
-}
\ No newline at end of file
+}
diff --git a/tests/run.sh b/tests/run.sh
index 9b5e3dd..45b4a02 100755
--- a/tests/run.sh
+++ b/tests/run.sh
@@ -5,6 +5,6 @@ set -e
 # Lets copy the code in a subdirectory of the tests, otherwise Composer cannot require the package.
 rsync -av .. fixtures/copy/ --exclude tests --exclude vendor
 
-COMPOSER=composer-test.json composer update -v
+COMPOSER=composer-test.json composer update -vvv
 
 #rm -rf fixtures/copy
diff --git a/tests/unitTests/AbstractDiscoveryTest.php b/tests/unitTests/AbstractDiscoveryTest.php
index 0758004..489c5f5 100644
--- a/tests/unitTests/AbstractDiscoveryTest.php
+++ b/tests/unitTests/AbstractDiscoveryTest.php
@@ -1,7 +1,7 @@
 <?php
 
 
-namespace TheCodingMachine\Discovery;
+namespace TheCodingMachine\Discovery\Tests;
 
 
 use Composer\Command\BaseCommand;
@@ -12,11 +12,11 @@
 use Composer\Package\RootPackage;
 use Composer\Repository\RepositoryInterface;
 use Composer\Repository\RepositoryManager;
+use PHPUnit\Framework\TestCase;
 use Symfony\Component\Console\Input\InputInterface;
 use Symfony\Component\Console\Output\BufferedOutput;
-use TheCodingMachine\Discovery\Commands\ListAssetTypesCommand;
 
-abstract class AbstractDiscoveryTest extends \PHPUnit_Framework_TestCase
+abstract class AbstractDiscoveryTest extends TestCase
 {
     protected function getInstallationManagerMock(string $installPath = null) : InstallationManager
     {
@@ -24,7 +24,7 @@ protected function getInstallationManagerMock(string $installPath = null) : Inst
 
         // Configure the stub.
         $installationManager->method('getInstallPath')
-            ->willReturn($installPath ?? 'tests/fixtures/package_a');
+            ->willReturn(realpath($installPath ?? 'tests/fixtures/package_a'));
 
         return $installationManager;
     }
diff --git a/tests/unitTests/AssetOperationTest.php b/tests/unitTests/AssetOperationTest.php
index 9209c12..4c5fc7d 100644
--- a/tests/unitTests/AssetOperationTest.php
+++ b/tests/unitTests/AssetOperationTest.php
@@ -1,11 +1,15 @@
 <?php
 
 
-namespace TheCodingMachine\Discovery;
+namespace TheCodingMachine\Discovery\Tests;
 
+use PHPUnit\Framework\TestCase;
+use InvalidArgumentException;
+use TheCodingMachine\Discovery\Asset;
+use TheCodingMachine\Discovery\AssetOperation;
 use TheCodingMachine\Discovery\Utils\JsonException;
 
-class AssetOperationTest extends \PHPUnit_Framework_TestCase
+class AssetOperationTest extends TestCase
 {
     public function testBuildFromString()
     {
diff --git a/tests/unitTests/AssetTest.php b/tests/unitTests/AssetTest.php
index d0e642f..e771e13 100644
--- a/tests/unitTests/AssetTest.php
+++ b/tests/unitTests/AssetTest.php
@@ -3,7 +3,9 @@
 namespace TheCodingMachine\Discovery;
 
 
-class AssetTest extends \PHPUnit_Framework_TestCase
+use PHPUnit\Framework\TestCase;
+
+class AssetTest extends TestCase
 {
     public function testToSimpleArray()
     {
diff --git a/tests/unitTests/AssetTypeTest.php b/tests/unitTests/AssetTypeTest.php
index 79f0aaa..b81094a 100644
--- a/tests/unitTests/AssetTypeTest.php
+++ b/tests/unitTests/AssetTypeTest.php
@@ -3,7 +3,9 @@
 
 namespace TheCodingMachine\Discovery;
 
-class AssetTypeTest extends \PHPUnit_Framework_TestCase
+use PHPUnit\Framework\TestCase;
+
+class AssetTypeTest extends TestCase
 {
     public function testAssetTypeName()
     {
diff --git a/tests/unitTests/AssetsBuilderTest.php b/tests/unitTests/AssetsBuilderTest.php
index 8f14083..fabf83f 100644
--- a/tests/unitTests/AssetsBuilderTest.php
+++ b/tests/unitTests/AssetsBuilderTest.php
@@ -1,12 +1,13 @@
 <?php
 
 
-namespace TheCodingMachine\Discovery;
+namespace TheCodingMachine\Discovery\Tests;
 
 use Composer\Installer\InstallationManager;
 use Composer\IO\BufferIO;
 use Composer\Package\Package;
 use Composer\Repository\RepositoryInterface;
+use TheCodingMachine\Discovery\AssetsBuilder;
 
 class AssetsBuilderTest extends AbstractDiscoveryTest
 {
diff --git a/tests/unitTests/Commands/AddAssetCommandTest.php b/tests/unitTests/Commands/AddAssetCommandTest.php
index efe6534..5a1941e 100644
--- a/tests/unitTests/Commands/AddAssetCommandTest.php
+++ b/tests/unitTests/Commands/AddAssetCommandTest.php
@@ -1,19 +1,15 @@
 <?php
 
 
-namespace TheCodingMachine\Discovery\Commands;
+namespace TheCodingMachine\Discovery\Tests\Commands;
 
 
-use Composer\Console\Application;
 use Symfony\Component\Console\Input\ArrayInput;
 use Symfony\Component\Console\Input\InputArgument;
 use Symfony\Component\Console\Input\InputDefinition;
-use Symfony\Component\Console\Input\InputInterface;
 use Symfony\Component\Console\Input\InputOption;
-use Symfony\Component\Console\Input\StringInput;
-use Symfony\Component\Console\Output\BufferedOutput;
-use Symfony\Component\Console\Tester\CommandTester;
-use TheCodingMachine\Discovery\AbstractDiscoveryTest;
+use TheCodingMachine\Discovery\Commands\AddAssetCommand;
+use TheCodingMachine\Discovery\Tests\AbstractDiscoveryTest;
 
 class AddAssetCommandTest extends AbstractDiscoveryTest
 {
@@ -59,7 +55,7 @@ public function testCallWithBadPriority()
 
         $result = $this->callCommand(new AddAssetCommand(), $input);
 
-        $this->assertContains('The priority must be a numeric value.', $result);
+        $this->assertStringContainsString('The priority must be a numeric value.', $result);
 
     }
 
diff --git a/tests/unitTests/Commands/CommandProviderTest.php b/tests/unitTests/Commands/CommandProviderTest.php
index 8985c00..518c59a 100644
--- a/tests/unitTests/Commands/CommandProviderTest.php
+++ b/tests/unitTests/Commands/CommandProviderTest.php
@@ -1,12 +1,14 @@
 <?php
 
 
-namespace TheCodingMachine\Discovery\Commands;
+namespace TheCodingMachine\Discovery\Tests\Commands;
 
 
+use PHPUnit\Framework\TestCase;
 use Symfony\Component\Console\Command\Command;
+use TheCodingMachine\Discovery\Commands\CommandProvider;
 
-class CommandProviderTest extends \PHPUnit_Framework_TestCase
+class CommandProviderTest extends TestCase
 {
     public function testCommandProvider()
     {
diff --git a/tests/unitTests/Commands/DumpCommandTest.php b/tests/unitTests/Commands/DumpCommandTest.php
index 1be49c0..430f8f2 100644
--- a/tests/unitTests/Commands/DumpCommandTest.php
+++ b/tests/unitTests/Commands/DumpCommandTest.php
@@ -1,19 +1,13 @@
 <?php
 
 
-namespace TheCodingMachine\Discovery\Commands;
+namespace TheCodingMachine\Discovery\Tests\Commands;
 
 
-use Composer\Console\Application;
 use Symfony\Component\Console\Input\ArrayInput;
-use Symfony\Component\Console\Input\InputArgument;
 use Symfony\Component\Console\Input\InputDefinition;
-use Symfony\Component\Console\Input\InputInterface;
-use Symfony\Component\Console\Input\InputOption;
-use Symfony\Component\Console\Input\StringInput;
-use Symfony\Component\Console\Output\BufferedOutput;
-use Symfony\Component\Console\Tester\CommandTester;
-use TheCodingMachine\Discovery\AbstractDiscoveryTest;
+use TheCodingMachine\Discovery\Commands\DumpCommand;
+use TheCodingMachine\Discovery\Tests\AbstractDiscoveryTest;
 
 class DumpCommandTest extends AbstractDiscoveryTest
 {
@@ -24,7 +18,7 @@ public function testCall()
 
         $result = $this->callCommand(new DumpCommand(), $input);
 
-        $this->assertContains('Discovery files successfully dumped in the .discovery directory.', $result);
+        $this->assertStringContainsString('Discovery files successfully dumped in the .discovery directory.', $result);
     }
 
 }
diff --git a/tests/unitTests/Commands/ListAssetTypesCommandTest.php b/tests/unitTests/Commands/ListAssetTypesCommandTest.php
index 1619087..046c80f 100644
--- a/tests/unitTests/Commands/ListAssetTypesCommandTest.php
+++ b/tests/unitTests/Commands/ListAssetTypesCommandTest.php
@@ -1,19 +1,15 @@
 <?php
 
 
-namespace TheCodingMachine\Discovery\Commands;
+namespace TheCodingMachine\Discovery\Tests\Commands;
 
 
-use Composer\Console\Application;
 use Symfony\Component\Console\Input\ArrayInput;
 use Symfony\Component\Console\Input\InputArgument;
 use Symfony\Component\Console\Input\InputDefinition;
-use Symfony\Component\Console\Input\InputInterface;
 use Symfony\Component\Console\Input\InputOption;
-use Symfony\Component\Console\Input\StringInput;
-use Symfony\Component\Console\Output\BufferedOutput;
-use Symfony\Component\Console\Tester\CommandTester;
-use TheCodingMachine\Discovery\AbstractDiscoveryTest;
+use TheCodingMachine\Discovery\Commands\ListAssetTypesCommand;
+use TheCodingMachine\Discovery\Tests\AbstractDiscoveryTest;
 
 class ListAssetTypesCommandTest extends AbstractDiscoveryTest
 {
@@ -31,9 +27,9 @@ public function testEmptyCall()
 
         $result = $this->callCommand(new ListAssetTypesCommand(), $input);
 
-        $this->assertContains('test-asset:', $result);
-        $this->assertContains('a1', $result);
-        $this->assertContains('a2', $result);
+        $this->assertStringContainsString('test-asset:', $result);
+        $this->assertStringContainsString('a1', $result);
+        $this->assertStringContainsString('a2', $result);
     }
 
     public function testWithAssetType()
@@ -42,9 +38,9 @@ public function testWithAssetType()
 
         $result = $this->callCommand(new ListAssetTypesCommand(), $input);
 
-        $this->assertContains('test-asset:', $result);
-        $this->assertContains('a1', $result);
-        $this->assertContains('a2', $result);
+        $this->assertStringContainsString('test-asset:', $result);
+        $this->assertStringContainsString('a1', $result);
+        $this->assertStringContainsString('a2', $result);
     }
 
     public function testJson()
@@ -63,6 +59,6 @@ public function testNoAssetType()
 
         $result = $this->callCommand(new ListAssetTypesCommand(), $input);
 
-        $this->assertContains('Could not find the "toto" asset type.', $result);
+        $this->assertStringContainsString('Could not find the "toto" asset type.', $result);
     }
 }
diff --git a/tests/unitTests/Commands/RemoveAssetCommandTest.php b/tests/unitTests/Commands/RemoveAssetCommandTest.php
index 12e807b..e6b7d85 100644
--- a/tests/unitTests/Commands/RemoveAssetCommandTest.php
+++ b/tests/unitTests/Commands/RemoveAssetCommandTest.php
@@ -1,19 +1,15 @@
 <?php
 
 
-namespace TheCodingMachine\Discovery\Commands;
+namespace TheCodingMachine\Discovery\Tests\Commands;
 
 
-use Composer\Console\Application;
 use Symfony\Component\Console\Input\ArrayInput;
 use Symfony\Component\Console\Input\InputArgument;
 use Symfony\Component\Console\Input\InputDefinition;
-use Symfony\Component\Console\Input\InputInterface;
-use Symfony\Component\Console\Input\InputOption;
-use Symfony\Component\Console\Input\StringInput;
-use Symfony\Component\Console\Output\BufferedOutput;
-use Symfony\Component\Console\Tester\CommandTester;
-use TheCodingMachine\Discovery\AbstractDiscoveryTest;
+use TheCodingMachine\Discovery\Commands\AddAssetCommand;
+use TheCodingMachine\Discovery\Commands\RemoveAssetCommand;
+use TheCodingMachine\Discovery\Tests\AbstractDiscoveryTest;
 
 class RemoveAssetCommandTest extends AbstractDiscoveryTest
 {
@@ -65,7 +61,7 @@ public function testRemoveNonExistingFromProject()
 
         $result = $this->callCommand(new RemoveAssetCommand(), $input);
 
-        $this->assertContains('There is no asset "not-exist" in asset type "not-exist".', $result);
+        $this->assertStringContainsString('There is no asset "not-exist" in asset type "not-exist".', $result);
     }
 
     public function testRemoveFromProject()
diff --git a/tests/unitTests/DiscoveryFileLoaderTest.php b/tests/unitTests/DiscoveryFileLoaderTest.php
index 9cd7143..0832f05 100644
--- a/tests/unitTests/DiscoveryFileLoaderTest.php
+++ b/tests/unitTests/DiscoveryFileLoaderTest.php
@@ -3,10 +3,11 @@
 
 namespace TheCodingMachine\Discovery;
 
+use PHPUnit\Framework\TestCase;
 use TheCodingMachine\Discovery\Utils\IOException;
 use TheCodingMachine\Discovery\Utils\JsonException;
 
-class DiscoveryFileLoaderTest extends \PHPUnit_Framework_TestCase
+class DiscoveryFileLoaderTest extends TestCase
 {
     public function testLoad()
     {
diff --git a/tests/unitTests/DiscoveryTest.php b/tests/unitTests/DiscoveryTest.php
index 22fd697..20736ea 100644
--- a/tests/unitTests/DiscoveryTest.php
+++ b/tests/unitTests/DiscoveryTest.php
@@ -3,9 +3,11 @@
 
 namespace TheCodingMachine\Discovery;
 
-class DiscoveryTest extends \PHPUnit_Framework_TestCase
+use PHPUnit\Framework\TestCase;
+
+class DiscoveryTest extends TestCase
 {
-    public function setUp()
+    public function setUp(): void
     {
         parent::setUp();
         // Let's load the autogenerated class for the unit tests.
@@ -37,7 +39,7 @@ public function testAssetType()
 
         $this->assertSame('a1', $result->getAssets()[0]->getValue());
         $this->assertSame('package/a', $result->getAssets()[0]->getPackage());
-        $this->assertSame('vendor/package/a/', $result->getAssets()[0]->getPackageDir());
+        $this->assertSame('fixtures/package_a/', $result->getAssets()[0]->getPackageDir());
     }
 
     public function testEmptyAssetType()
diff --git a/tests/unitTests/DumperTest.php b/tests/unitTests/DumperTest.php
index f24d277..c659228 100644
--- a/tests/unitTests/DumperTest.php
+++ b/tests/unitTests/DumperTest.php
@@ -1,9 +1,11 @@
 <?php
 
 
-namespace TheCodingMachine\Discovery;
+namespace TheCodingMachine\Discovery\Tests;
 
 
+use TheCodingMachine\Discovery\Dumper;
+
 class DumperTest extends AbstractDiscoveryTest
 {
     public function testDumpDiscoveryFiles()
diff --git a/tests/unitTests/ImmutableAssetTypeTest.php b/tests/unitTests/ImmutableAssetTypeTest.php
index 332de82..3ed4f45 100644
--- a/tests/unitTests/ImmutableAssetTypeTest.php
+++ b/tests/unitTests/ImmutableAssetTypeTest.php
@@ -3,7 +3,9 @@
 
 namespace TheCodingMachine\Discovery;
 
-class ImmutableAssetTypeTest extends \PHPUnit_Framework_TestCase
+use PHPUnit\Framework\TestCase;
+
+class ImmutableAssetTypeTest extends TestCase
 {
     public function testFromArray()
     {
diff --git a/tests/unitTests/PackagesOrdererTest.php b/tests/unitTests/PackagesOrdererTest.php
index c4b2d44..9be4060 100644
--- a/tests/unitTests/PackagesOrdererTest.php
+++ b/tests/unitTests/PackagesOrdererTest.php
@@ -1,13 +1,15 @@
 <?php
 
 
-namespace TheCodingMachine\Discovery;
+namespace TheCodingMachine\Discovery\Tests;
 
+use Composer\Semver\Constraint\Constraint;
 use Composer\Semver\VersionParser;
 use Composer\Package\Link;
-use Composer\TestCase;
+use PHPUnit\Framework\TestCase;
+use TheCodingMachine\Discovery\PackagesOrderer;
 
-class PackagesOrdererTest extends \PHPUnit_Framework_TestCase
+class PackagesOrdererTest extends TestCase
 {
     private static $parser;
 
@@ -36,10 +38,10 @@ public function testOrderer()
         /* @var $packageB \Composer\Package\Package */
         /* @var $packageC \Composer\Package\Package */
         $packageB->setRequires([
-            new Link('package/b', 'package/za')
+            new Link('package/b', 'package/za', new Constraint('=', '*'))
         ]);
         $packageC->setRequires([
-            new Link('package/c', 'package/b')
+            new Link('package/c', 'package/b', new Constraint('=', '*'))
         ]);
 
         $result = PackagesOrderer::reorderPackages([$packageC, $packageB, $packageA]);