diff --git a/CHANGELOG.md b/CHANGELOG.md
index a6feca6..b1b91e3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Added
 - The new `beforeExecutionHook` hook lets your GraphQL controller (using the `HandlesGraphqlRequests` trait) inspect the schema and query before entering the execution phase.
 
+### Fixed
+- Upgrade graham-campbell/testbench@^5.6 because of breaking change in `GrahamCampbell\TestBench\AbstractPackageTestCase`.
+
 
 ## [5.0.0] - 2021-03-11
 
diff --git a/composer.json b/composer.json
index 41a86b7..c7820f6 100644
--- a/composer.json
+++ b/composer.json
@@ -46,7 +46,7 @@
         "webonyx/graphql-php": "^14.3.0"
     },
     "require-dev": {
-        "graham-campbell/testbench": "^5.2",
+        "graham-campbell/testbench": "^5.6",
         "mockery/mockery": "^1.0",
         "phpunit/phpunit": "^7.0|^8.0|^9.0",
         "squizlabs/php_codesniffer": "^3.4"
diff --git a/tests/AbstractTestCase.php b/tests/AbstractTestCase.php
index 963a7e9..7ec729e 100644
--- a/tests/AbstractTestCase.php
+++ b/tests/AbstractTestCase.php
@@ -7,7 +7,7 @@
 
 abstract class AbstractTestCase extends AbstractPackageTestCase
 {
-    protected function getServiceProviderClass($app)
+    protected function getServiceProviderClass()
     {
         return ServiceProvider::class;
     }