diff --git a/.github/workflows/unit-tests.yml b/.github/workflows/unit-tests.yml
index ed8c22b..85d91ee 100644
--- a/.github/workflows/unit-tests.yml
+++ b/.github/workflows/unit-tests.yml
@@ -40,4 +40,14 @@ jobs:
           composer-options: --ignore-platform-reqs
 
       - name: Run tests
-        run: composer run phpunit -- --coverage-text
+        run: composer run phpunit -- --coverage-clover .phpunit.cache/clover.xml
+
+      - name: Upload coverage reports to Codecov
+        if: ${{ success() && matrix.php == '8.2' }}
+        uses: codecov/codecov-action@v3
+        env:
+          CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
+        with:
+          files: ./.phpunit.cache/clover.xml
+          fail_ci_if_error: true
+          verbose: true
diff --git a/README.md b/README.md
index e200ed8..1325e1a 100644
--- a/README.md
+++ b/README.md
@@ -3,6 +3,7 @@
 [![Latest Version](https://img.shields.io/github/release/Art4/json-api-client.svg)](https://github.com/Art4/json-api-client/releases)
 [![Software License](https://img.shields.io/badge/license-GPL3-brightgreen.svg)](LICENSE)
 [![Build Status](https://github.com/art4/json-api-client/actions/workflows/unit-tests.yml/badge.svg?branch=v1.x)](https://github.com/Art4/json-api-client/actions)
+[![codecov](https://codecov.io/gh/Art4/json-api-client/graph/badge.svg?token=5oNNDEUWgZ)](https://codecov.io/gh/Art4/json-api-client)
 [![Total Downloads](https://img.shields.io/packagist/dt/art4/json-api-client.svg)](https://packagist.org/packages/art4/json-api-client)
 
 JsonApiClient :construction_worker_woman: is a PHP Library to validate and handle the response body from a [JSON API](http://jsonapi.org) Server.
diff --git a/phpunit.xml b/phpunit.xml
index 03c0f13..002a138 100644
--- a/phpunit.xml
+++ b/phpunit.xml
@@ -19,12 +19,6 @@
       <directory suffix="Test.php">tests/Functional/</directory>
       <directory suffix="Test.php">tests/BC/</directory>
     </testsuite>
-    <testsuite name="unit">
-      <directory suffix="Test.php">tests/Unit/</directory>
-    </testsuite>
-    <testsuite name="functional">
-      <directory suffix="Test.php">tests/Functional/</directory>
-    </testsuite>
   </testsuites>
   <source>
     <include>
diff --git a/src/V1/Factory.php b/src/V1/Factory.php
index 8d99636..f1bab75 100644
--- a/src/V1/Factory.php
+++ b/src/V1/Factory.php
@@ -67,7 +67,11 @@ public function make($name, array $args = []): Accessable
         $object = $class->newInstanceArgs($args);
 
         if (! $object instanceof Accessable) {
-            throw new FactoryException($this->classes[$name] . ' must be instance of `Art4\JsonApiClient\Accessable`');
+            throw new FactoryException(sprintf(
+                '%s must be instance of `%s`',
+                $this->classes[$name],
+                Accessable::class
+            ));
         }
 
         return $object;
diff --git a/tests/Unit/V1/FactoryTest.php b/tests/Unit/V1/FactoryTest.php
index a96aaef..5d1b6b0 100644
--- a/tests/Unit/V1/FactoryTest.php
+++ b/tests/Unit/V1/FactoryTest.php
@@ -13,6 +13,7 @@
 use Art4\JsonApiClient\V1\Factory;
 use Art4\JsonApiClient\V1\ResourceNull;
 use PHPUnit\Framework\TestCase;
+use stdClass;
 
 class FactoryTest extends TestCase
 {
@@ -49,4 +50,18 @@ public function testMakeAnUndefindedClassThrowsException()
 
         $class = $factory->make('NotExistent');
     }
+
+    public function testMakeWithClassNotImplementingAccessableThrowsException()
+    {
+        $factory = new Factory([
+            'Default' => stdClass::class,
+        ]);
+
+        $this->expectException(FactoryException::class);
+        $this->expectExceptionMessage(
+            'stdClass must be instance of `Art4\JsonApiClient\Accessable`'
+        );
+
+        $class = $factory->make('Default');
+    }
 }