Upgrade to php unit new test case

Author: unicodeveloper

.travis.yml

@@ -1,7 +1,7 @@
 language: php
 
 php:
-  - 7.2
+  - 7.3
   - hhvm
 
 matrix:

tests/HelpersTest.php

@@ -2,9 +2,9 @@
 
 namespace Unicodeveloper\Paystack\Test;
 
-use PHPUnit_Framework_TestCase;
+use PHPUnit\Framework\TestCase;
 
-class HelpersTest extends PHPUnit_Framework_TestCase {
+class HelpersTest extends TestCase {
 
     /**
      * Tests that helper returns

tests/PaystackTest.php

@@ -13,12 +13,12 @@
 
 use Mockery as m;
 use GuzzleHttp\Client;
-use PHPUnit_Framework_TestCase;
+use PHPUnit\Framework\TestCase;
 use Unicodeveloper\Paystack\Paystack;
 use Illuminate\Support\Facades\Config;
 use Illuminate\Support\Facades\Facade as Facade;
 
-class PaystackTest extends PHPUnit_Framework_TestCase
+class PaystackTest extends TestCase
 {
     protected $paystack;