Tests: PHP shared opcache test added.

test/php/opcache/index.php

@@ -0,0 +1,18 @@
+<?php
+
+$pid = getmypid();
+
+header('X-Pid: ' . $pid);
+
+if (function_exists('opcache_is_script_cached')) {
+    if (opcache_is_script_cached(__DIR__ . '/test.php')) {
+        header('X-Cached: 1');
+    } else {
+        header('X-Cached: 0');
+        opcache_compile_file(__DIR__ . '/test.php');
+    }
+} else {
+    header('X-Cached: -1');
+}
+
+?>

test/php/opcache/test.php

@@ -0,0 +1 @@
+<?php phpinfo(); ?>