add new test to test memory usage

Author: deminy

tests/005_memory_usage.phpt

@@ -0,0 +1,31 @@
+--TEST--
+Test memory usage
+--EXTENSIONS--
+bsdiff
+--FILE--
+<?php
+$old_file     = __DIR__ . '/005_old.out';
+$new_file     = __DIR__ . '/005_new.out';
+$diff_file    = __DIR__ . '/005_diff.out';
+$patched_file = __DIR__ . '/005_patched.out';
+
+file_put_contents($old_file, str_repeat("Hello World", 1997));
+file_put_contents($new_file, str_repeat("Hello PHP", 1999));
+
+$i = 0;
+
+$mem0 = memory_get_usage();
+
+for (; $i <= 100; $i++) {
+    if (file_exists($diff_file)) unlink($diff_file);
+    if (file_exists($patched_file)) unlink($patched_file);
+
+    bsdiff_diff($old_file, $new_file, $diff_file);
+    bsdiff_patch($old_file, $patched_file, $diff_file);
+}
+
+$mem1 = memory_get_usage();
+var_dump($mem1 - $mem0);
+?>
+--EXPECT--
+int(0)