diff --git a/.travis.yml b/.travis.yml
index 007011f1b..68c29d067 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -34,7 +34,7 @@ install:
     - rm $HOME/.phpenv/versions/$(phpenv version-name)/etc/conf.d/xdebug.ini;
     - echo "memory_limit=2048M" >> ~/.phpenv/versions/$(phpenv version-name)/etc/conf.d/travis.ini
     - composer require symfony/symfony:${SYMFONY_VERSION} --no-update
-    - composer update
+    - composer install --ignore-platform-reqs # ext-amqp is not installed
     - if [ "$FUNCTIONAL_TESTS" = true ]; then docker --version; fi
     - if [ "$FUNCTIONAL_TESTS" = true ]; then docker-compose --version; fi
     - if [ "$FUNCTIONAL_TESTS" = true ]; then bin/dev -b; fi
diff --git a/pkg/amqp-ext/.travis.yml b/pkg/amqp-ext/.travis.yml
index 42374ddc7..ad53bf6b4 100644
--- a/pkg/amqp-ext/.travis.yml
+++ b/pkg/amqp-ext/.travis.yml
@@ -15,7 +15,7 @@ cache:
 
 install:
     - composer self-update
-    - composer install --prefer-source
+    - composer install --prefer-source --ignore-platform-reqs # ext-amqp is not installed
 
 script:
     - vendor/bin/phpunit --exclude-group=functional
diff --git a/pkg/enqueue-bundle/DependencyInjection/Compiler/BuildExtensionsPass.php b/pkg/enqueue-bundle/DependencyInjection/Compiler/BuildExtensionsPass.php
index c86b5a35d..31dcee799 100644
--- a/pkg/enqueue-bundle/DependencyInjection/Compiler/BuildExtensionsPass.php
+++ b/pkg/enqueue-bundle/DependencyInjection/Compiler/BuildExtensionsPass.php
@@ -24,7 +24,7 @@ public function process(ContainerBuilder $container)
             }
         }
 
-        ksort($groupByPriority);
+        krsort($groupByPriority, SORT_NUMERIC);
 
         $flatExtensions = [];
         foreach ($groupByPriority as $extension) {
diff --git a/pkg/enqueue-bundle/Tests/Unit/DependencyInjection/Compiler/BuildExtensionsPassTest.php b/pkg/enqueue-bundle/Tests/Unit/DependencyInjection/Compiler/BuildExtensionsPassTest.php
index 8e4aa54bc..0d57167dd 100644
--- a/pkg/enqueue-bundle/Tests/Unit/DependencyInjection/Compiler/BuildExtensionsPassTest.php
+++ b/pkg/enqueue-bundle/Tests/Unit/DependencyInjection/Compiler/BuildExtensionsPassTest.php
@@ -73,9 +73,9 @@ public function testShouldOrderExtensionsByPriority()
 
         $orderedExtensions = $extensions->getArgument(0);
 
-        $this->assertEquals(new Reference('bar_extension'), $orderedExtensions[0]);
+        $this->assertEquals(new Reference('foo_extension'), $orderedExtensions[0]);
         $this->assertEquals(new Reference('baz_extension'), $orderedExtensions[1]);
-        $this->assertEquals(new Reference('foo_extension'), $orderedExtensions[2]);
+        $this->assertEquals(new Reference('bar_extension'), $orderedExtensions[2]);
     }
 
     public function testShouldAssumePriorityZeroIfPriorityIsNotSet()
@@ -103,8 +103,8 @@ public function testShouldAssumePriorityZeroIfPriorityIsNotSet()
 
         $orderedExtensions = $extensions->getArgument(0);
 
-        $this->assertEquals(new Reference('baz_extension'), $orderedExtensions[0]);
+        $this->assertEquals(new Reference('bar_extension'), $orderedExtensions[0]);
         $this->assertEquals(new Reference('foo_extension'), $orderedExtensions[1]);
-        $this->assertEquals(new Reference('bar_extension'), $orderedExtensions[2]);
+        $this->assertEquals(new Reference('baz_extension'), $orderedExtensions[2]);
     }
 }