h_difference works

src/bindings/php/Tests/DifferenceTest.php

@@ -0,0 +1,25 @@
+<?php
+include_once 'hammer.php';
+
+class DifferenceTest extends PHPUnit_Framework_TestCase
+{
+    protected $parser;
+
+    protected function setUp()
+    {
+        $this->parser = h_difference(h_token("ab"), ch("a"));
+    }
+
+    public function testSuccess()
+    {
+        $result = h_parse($this->parser, "ab");
+        $this->assertEquals("ab", $result);
+    }
+
+    public function testFailure()
+    {
+        $result = h_parse($this->parser, "a");
+        $this->assertEquals(NULL, $result);
+    }
+}
+?>