diff --git a/.gitignore b/.gitignore
index 0602d69..273fe7b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,3 +3,4 @@ phpunit.xml
 vendor
 bin/
 .php_cs.cache
+.phpunit.*
diff --git a/README.md b/README.md
index cbdacbe..94e26ab 100644
--- a/README.md
+++ b/README.md
@@ -15,6 +15,16 @@ Swap allows you to retrieve currency exchange rates from various services such a
 $ composer require php-http/curl-client nyholm/psr7 php-http/message florianv/laravel-swap
 ```
 
+### Laravel 5.7 or lesser
+
+If you use cache, add also PSR-6 adapter and PSR-16 bridge cache dependencies :
+
+```bash
+$ composer require cache/illuminate-adapter cache/simple-cache-bridge
+```
+
+These dependencies are not required with Laravel 5.8 or greater which [implements PSR-16](https://github.com/laravel/framework/pull/27217).
+
 ### Laravel 5.5+
 
 If you don't use auto-discovery, add the `ServiceProvider` to the providers array in `config/app.php`:
diff --git a/composer.json b/composer.json
index 0d481a5..f6a638c 100644
--- a/composer.json
+++ b/composer.json
@@ -32,12 +32,10 @@
     },
     "require": {
         "php": "^7.1.3",
-        "florianv/swap": "^4.0",
-        "cache/illuminate-adapter": "^0.2.0",
-        "cache/simple-cache-bridge": "^1.0"
+        "florianv/swap": "^4.0"
     },
     "require-dev": {
-        "graham-campbell/testbench": "~5.2",
+        "graham-campbell/testbench": "^5.3",
         "php-http/guzzle6-adapter": "^1.0",
         "nyholm/psr7": "^1.0"
     },
diff --git a/doc/readme.md b/doc/readme.md
index 6a8cf9a..838f754 100644
--- a/doc/readme.md
+++ b/doc/readme.md
@@ -56,6 +56,16 @@ Copy the package config to your local config with the publish command:
 $ php artisan vendor:publish --provider="Swap\Laravel\SwapServiceProvider"
 ```
 
+__Laravel 5.7 or lesser :__
+
+If you use cache, add also PSR-6 adapter and PSR-16 bridge cache dependencies :
+
+```bash
+$ composer require cache/illuminate-adapter cache/simple-cache-bridge
+```
+
+These dependencies are not required with Laravel 5.8 or greater which [implements PSR-16](https://github.com/laravel/framework/pull/27217).
+
 ### Lumen
 
 Configure the Service Provider and alias:
diff --git a/src/SwapServiceProvider.php b/src/SwapServiceProvider.php
index 6bab127..9b47016 100644
--- a/src/SwapServiceProvider.php
+++ b/src/SwapServiceProvider.php
@@ -99,9 +99,26 @@ private function getConfigPath($path = '')
     private function getSimpleCache()
     {
         if ($cache = $this->app->config->get('swap.cache')) {
-            $store = $this->app['cache']->store($cache)->getStore();
+            $store = $this->app['cache']->store($cache);
 
-            return new SimpleCacheBridge(new IlluminateCachePool($store));
+            // Check simple cache PSR-16 compatibility
+            if ($store instanceof \Psr\SimpleCache\CacheInterface) {
+                return $store;
+            }
+
+            // Ensure PSR-6 adapter class exists
+            if (! class_exists(IlluminateCachePool::class)) {
+                throw new \Exception("cache/illuminate-adapter dependency is missing");
+            }
+
+            // Ensure PSR-16 bridge class exists
+            if (! class_exists(SimpleCacheBridge::class)) {
+                throw new \Exception("cache/simple-cache-bridge dependency is missing");
+            }
+
+            return new SimpleCacheBridge(
+                new IlluminateCachePool($store->getStore())
+            );
         }
 
         return null;
diff --git a/tests/SwapServiceProviderTest.php b/tests/SwapServiceProviderTest.php
index abfe5b8..8c06915 100644
--- a/tests/SwapServiceProviderTest.php
+++ b/tests/SwapServiceProviderTest.php
@@ -21,12 +21,11 @@ class SwapServiceProviderTest extends AbstractTestCase
 {
     use ServiceProviderTrait;
 
-    /**
-     * @expectedException \InvalidArgumentException
-     * @expectedExceptionMessage The "access_key" option must be provided.
-     */
     public function testMissingServiceConfig()
     {
+        $this->expectException(\InvalidArgumentException::class);
+        $this->expectExceptionMessage('The "access_key" option must be provided.');
+
         $this->app->config->set('swap.services', [
             'currency_layer' => true,
         ]);
@@ -34,12 +33,11 @@ public function testMissingServiceConfig()
         $this->app['swap'];
     }
 
-    /**
-     * @expectedException \LogicException
-     * @expectedExceptionMessage The service "unknown" is not registered.
-     */
     public function testUnknownService()
     {
+        $this->expectException(\LogicException::class);
+        $this->expectExceptionMessage('The service "unknown" is not registered.');
+
         $this->app->config->set('swap.services', [
             'unknown' => true,
         ]);
@@ -49,7 +47,7 @@ public function testUnknownService()
 
     public function testEmptyServices()
     {
-        $this->app['swap'];
+        Assert::assertInstanceOf(Swap::class, $this->app['swap']);
     }
 
     public function testSwapIsInjectable()