Minor - remove notice

tests/simpletest/shell_tester.php

@@ -38,6 +38,7 @@ class SimpleShell {
      */
     function execute($command) {
         $this->_output = false;
+        $ret = null;
         exec($command, $this->_output, $ret);
         return $ret;
     }

tests/simpletest/socket.php

@@ -87,6 +87,8 @@ class SimpleSocket extends SimpleStickyError {
      */
     function SimpleSocket($host, $port, $timeout, $block_size = 255) {
         $this->SimpleStickyError();
+        $error_number = 0;
+        $error = '';
         if (! ($this->_handle = $this->_openSocket($host, $port, $error_number, $error, $timeout))) {
             $this->_setError("Cannot open [$host:$port] with [$error] within [$timeout] seconds");
             return;

tests/simpletest/test_case.php

@@ -541,6 +541,7 @@ class TestSuite {
      *    @access public
      */
     function add(&$test_case) {
+        $class = null;
         if (! is_string($test_case)) {
             $this->_test_cases[] = &$test_case;
         } elseif (TestSuite::getBaseTestCase($class) == 'testsuite') {