MDL-39465 detect environment problems in tests

This should help explain why something else fails.

lib/tests/environment_test.php

@@ -0,0 +1,45 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Moodle environment test.
+ *
+ * @package    core
+ * @category   phpunit
+ * @copyright  2013 Petr Skoda {@link http://skodak.org}
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+defined('MOODLE_INTERNAL') || die();
+
+
+/**
+ * Do standard environment.xml tests.
+ */
+class environment_testcase extends advanced_testcase {
+
+    public function test_environment() {
+        global $CFG;
+
+        require_once($CFG->libdir.'/environmentlib.php');
+        list($envstatus, $environment_results) = check_moodle_environment(normalize_version($CFG->release), ENV_SELECT_RELEASE);
+
+        $this->assertNotEmpty($envstatus);
+        foreach ($environment_results as $environment_result) {
+            $this->assertTrue($environment_result->getStatus(), "Problem detected in environment ($environment_result->part:$environment_result->part), fix all warnings and errors!");
+        }
+    }
+}