diff --git a/src/JsonSchema/Constraints/Format.php b/src/JsonSchema/Constraints/Format.php
index 9262d6b..9bcab3e 100644
--- a/src/JsonSchema/Constraints/Format.php
+++ b/src/JsonSchema/Constraints/Format.php
@@ -92,6 +92,7 @@ class Format extends Constraint
                 break;
 
             case 'ip-address':
+            case 'ipv4':
                 if (null === filter_var($element, FILTER_VALIDATE_IP, FILTER_NULL_ON_FAILURE | FILTER_FLAG_IPV4)) {
                     $this->addError($path, "Invalid IP address");
                 }
@@ -104,6 +105,7 @@ class Format extends Constraint
                 break;
 
             case 'host-name':
+            case 'hostname':
                 if (!$this->validateHostname($element)) {
                     $this->addError($path, "Invalid hostname");
                 }
diff --git a/tests/JsonSchema/Tests/Drafts/Draft4Test.php b/tests/JsonSchema/Tests/Drafts/Draft4Test.php
new file mode 100644
index 0000000..e51e06a
--- /dev/null
+++ b/tests/JsonSchema/Tests/Drafts/Draft4Test.php
@@ -0,0 +1,36 @@
+<?php
+
+namespace JsonSchema\Tests\Drafts;
+
+class Draft4Test extends BaseDraftTestCase
+{
+    protected function getFilePaths()
+    {
+        return array(
+            realpath(__DIR__ . $this->relativeTestsRoot . '/draft4'),
+            realpath(__DIR__ . $this->relativeTestsRoot . '/draft4/optional')
+        );
+    }
+
+    protected function getSkippedTests()
+    {
+        return array(
+            // Not Yet Implemented
+            'allOf.json',
+            'anyOf.json',
+            'definitions.json',
+            'maxProperties.json',
+            'minProperties.json',
+            'multipleOf.json',
+            'not.json',
+            'oneOf.json',
+            // Partially Implemented
+            'ref.json',
+            'refRemote.json',
+            // Optional
+            'bignum.json',
+            'zeroTerminatedFloats.json'
+        );
+    }
+
+}
\ No newline at end of file