diff --git a/tests/Iyzipay/Tests/CurlTest.php b/tests/Iyzipay/Tests/CurlTest.php
index c7a65869..ecddb88a 100644
--- a/tests/Iyzipay/Tests/CurlTest.php
+++ b/tests/Iyzipay/Tests/CurlTest.php
@@ -4,7 +4,7 @@
 
 use Iyzipay\Curl;
 
-class CurlTest extends \PHPUnit_Framework_TestCase
+class CurlTest extends TestCase
 {
     public function test_should_exec_curl()
     {
@@ -13,7 +13,8 @@ public function test_should_exec_curl()
             CURLOPT_CUSTOMREQUEST => "GET",
             CURLOPT_RETURNTRANSFER => true,
             CURLOPT_VERBOSE => false,
-            CURLOPT_HEADER => false));
+            CURLOPT_HEADER => false
+        ));
 
         $this->assertNotNull($ret);
         $this->assertFalse($ret);
diff --git a/tests/Iyzipay/Tests/DefaultHttpClientTest.php b/tests/Iyzipay/Tests/DefaultHttpClientTest.php
index 72ccde38..2a51bba1 100644
--- a/tests/Iyzipay/Tests/DefaultHttpClientTest.php
+++ b/tests/Iyzipay/Tests/DefaultHttpClientTest.php
@@ -4,11 +4,11 @@
 
 use Iyzipay\DefaultHttpClient;
 
-class DefaultHttpClientTest extends \PHPUnit_Framework_TestCase
+class DefaultHttpClientTest extends TestCase
 {
     private $curl;
 
-    public function setUp()
+    public function setUp(): void
     {
         $this->curl = $this->getMockBuilder("Curl")
             ->setMethods(array("exec"))
@@ -47,7 +47,7 @@ public function test_should_make_http_getV2()
             ))
             ->willReturn("result");
 
-        $result = DefaultHttpClient::create($this->curl)->getV2("url","header");
+        $result = DefaultHttpClient::create($this->curl)->getV2("url", "header");
 
         $this->assertEquals("result", $result);
     }
diff --git a/tests/Iyzipay/Tests/FileBase64Encoder.php b/tests/Iyzipay/Tests/FileBase64Encoder.php
deleted file mode 100644
index 340ff170..00000000
--- a/tests/Iyzipay/Tests/FileBase64Encoder.php
+++ /dev/null
@@ -1,18 +0,0 @@
-<?php
-
-namespace Iyzipay\Tests;
-
-use Iyzipay\FileBase64Encoder;
-
-class FileBase64EncoderTest extends \PHPUnit_Framework_TestCase
-{
-    public function test_should_base64file_helper()
-    {
-        $imagePath = __DIR__ . '/images/sample_image.jpg';
-        $base64FileHelper = new FileBase64Encoder();
-        $encodedImage     = $base64FileHelper->encode($imagePath);
-
-        $this->assertNotNull($encodedImage);
-
-    }
-}
\ No newline at end of file