Add tests for SimpleSAML\Utils\Random.

tests/lib/SimpleSAML/Utils/RandomTest.php

+<?php
+
+
+/**
+ * Tests for SimpleSAML\Utils\Random.
+ */
+class RandomTest extends PHPUnit_Framework_TestCase
+{
+
+    public function testGenerateID()
+    {
+        // check that it always starts with an underscore
+        $this->assertStringStartsWith('_', SimpleSAML\Utils\Random::generateID());
+
+        // check the length
+        $this->assertEquals(SimpleSAML\Utils\Random::ID_LENGTH, strlen(SimpleSAML\Utils\Random::generateID()));
+    }
+}