diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..4f4acd3
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+vendor/
+composer.lock
\ No newline at end of file
diff --git a/composer.json b/composer.json
index 3d64e61..1c32ab7 100644
--- a/composer.json
+++ b/composer.json
@@ -16,11 +16,14 @@
     }
   ],
   "require": {
-      "php": ">=5.3.0"
+      "php": ">=5.4"
   },
   "autoload": {
     "files": [
       "src/IndieWeb/link_rel_parser.php"
     ]    
+  },
+  "require-dev": {
+    "yoast/phpunit-polyfills": "^1.0"
   }
-}
\ No newline at end of file
+}
diff --git a/tests/BasicTest.php b/tests/BasicTest.php
index 2b373c0..db71a0d 100644
--- a/tests/BasicTest.php
+++ b/tests/BasicTest.php
@@ -1,9 +1,8 @@
 <?php
-class BasicTest extends PHPUnit_Framework_TestCase {
 
-  public function setUp() {
-  }
+use PHPUnit\Framework\TestCase;
 
+class BasicTest extends TestCase {
   private function _testEquals($expected, $headers) {
     $result = IndieWeb\http_rels($headers);
     $this->assertEquals($expected, $result);
diff --git a/tests/bootstrap.php b/tests/bootstrap.php
index 69cbd1b..b122fd9 100644
--- a/tests/bootstrap.php
+++ b/tests/bootstrap.php
@@ -1,4 +1,4 @@
 <?php
 
-require dirname(__DIR__) . '/src/IndieWeb/link_rel_parser.php';
+require_once dirname(__DIR__) . '/src/IndieWeb/link_rel_parser.php';