diff --git a/README.md b/README.md
index 1bb43b4..f820ffa 100644
--- a/README.md
+++ b/README.md
@@ -83,7 +83,7 @@ $generator = function () {
     yield 2;
 };
 
-$reduce = static function ($carry, $item) {
+$reduce = function ($carry, $item) {
     return $carry + $item;
 };
 
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index 9ca55d7..ed2e5d0 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -17,12 +17,7 @@
 >
     <testsuites>
         <testsuite name="Test Suite">
-           <file>tests/TestIsIterable.php</file>
-           <file>tests/TestIterableToArray.php</file>
-           <file>tests/TestIterableToTraversable.php</file>
-           <file>tests/TestIterableFilter.php</file>
-           <file>tests/TestIterableMap.php</file>
-           <file>tests/TestIterableObject.php</file>
+            <directory>tests</directory>
         </testsuite>
     </testsuites>
     <filter>
diff --git a/tests/TestIsIterable.php b/tests/IsIterableTest.php
similarity index 95%
rename from tests/TestIsIterable.php
rename to tests/IsIterableTest.php
index 8426ed8..7449010 100644
--- a/tests/TestIsIterable.php
+++ b/tests/IsIterableTest.php
@@ -2,7 +2,7 @@
 
 use PHPUnit\Framework\TestCase;
 
-class TestIsIterable extends TestCase
+final class IsIterableTest extends TestCase
 {
 
     public function testFunctionExists()
diff --git a/tests/TestIterableFilter.php b/tests/IterableFilterTest.php
similarity index 90%
rename from tests/TestIterableFilter.php
rename to tests/IterableFilterTest.php
index cd9d22e..e222545 100644
--- a/tests/TestIterableFilter.php
+++ b/tests/IterableFilterTest.php
@@ -1,6 +1,8 @@
 <?php
 
-class TestIterableFilter extends \PHPUnit\Framework\TestCase
+use PHPUnit\Framework\TestCase;
+
+final class IterableFilterTest extends TestCase
 {
 
     public function testArrayFilter()
@@ -31,4 +33,4 @@ public function testInvalidIterable()
         };
         iterable_filter('foo', $filter);
     }
-}
\ No newline at end of file
+}
diff --git a/tests/TestIterableMap.php b/tests/IterableMapTest.php
similarity index 89%
rename from tests/TestIterableMap.php
rename to tests/IterableMapTest.php
index 26d2811..260e7c9 100644
--- a/tests/TestIterableMap.php
+++ b/tests/IterableMapTest.php
@@ -1,6 +1,8 @@
 <?php
 
-class TestIterableMap extends \PHPUnit\Framework\TestCase
+use PHPUnit\Framework\TestCase;
+
+final class IterableMapTest extends TestCase
 {
 
     public function testArrayMap()
@@ -27,4 +29,4 @@ public function testInvalidIterable()
         };
         iterable_map('foo', $filter);
     }
-}
\ No newline at end of file
+}
diff --git a/tests/TestIterableObject.php b/tests/IterableObjectTest.php
similarity index 97%
rename from tests/TestIterableObject.php
rename to tests/IterableObjectTest.php
index 108a4ee..28beff2 100644
--- a/tests/TestIterableObject.php
+++ b/tests/IterableObjectTest.php
@@ -1,6 +1,8 @@
 <?php
 
-class TestIterableObject extends \PHPUnit\Framework\TestCase
+use PHPUnit\Framework\TestCase;
+
+final class IterableObjectTest extends TestCase
 {
 
     /**
diff --git a/tests/TestIterableReduce.php b/tests/IterableReduceTest.php
similarity index 75%
rename from tests/TestIterableReduce.php
rename to tests/IterableReduceTest.php
index 99b7709..5f125c6 100644
--- a/tests/TestIterableReduce.php
+++ b/tests/IterableReduceTest.php
@@ -2,12 +2,12 @@
 
 use PHPUnit\Framework\TestCase;
 
-final class TestIterableReduce extends TestCase
+final class IterableReduceTest extends TestCase
 {
     public function testArrayReduce()
     {
         $iterable = array(1, 2);
-        $reduce = static function ($carry, $item) {
+        $reduce = function ($carry, $item) {
             return $carry + $item;
         };
         self::assertSame(3, iterable_reduce($iterable, $reduce, 0));
@@ -16,7 +16,7 @@ public function testArrayReduce()
     public function testTraversableReduce()
     {
         $iterable = SplFixedArray::fromArray(array(1, 2));
-        $reduce = static function ($carry, $item) {
+        $reduce = function ($carry, $item) {
             return $carry + $item;
         };
         self::assertSame(3, iterable_reduce($iterable, $reduce, 0));
diff --git a/tests/TestIterableToArray.php b/tests/IterableToArrayTest.php
similarity index 97%
rename from tests/TestIterableToArray.php
rename to tests/IterableToArrayTest.php
index 8d0de25..1808c71 100644
--- a/tests/TestIterableToArray.php
+++ b/tests/IterableToArrayTest.php
@@ -2,7 +2,7 @@
 
 use PHPUnit\Framework\TestCase;
 
-class TestIterableToArray extends TestCase
+final class IterableToArrayTest extends TestCase
 {
 
     public function testFunctionExists()
diff --git a/tests/TestIterableToTraversable.php b/tests/IterableToTraversableTest.php
similarity index 94%
rename from tests/TestIterableToTraversable.php
rename to tests/IterableToTraversableTest.php
index 2038065..cb6f45f 100644
--- a/tests/TestIterableToTraversable.php
+++ b/tests/IterableToTraversableTest.php
@@ -2,7 +2,7 @@
 
 use PHPUnit\Framework\TestCase;
 
-class TestIterableToTraversable extends TestCase
+final class IterableToTraversableTest extends TestCase
 {
 
     public function testFunctionExists()