added tests

tests/DBTest.php

@@ -0,0 +1,20 @@
+<?php
+use crodas\InfluxPHP\Client;
+
+class DBTest extends \phpunit_framework_testcase
+{
+    public function testCreate()
+    {
+        $client = new Client;
+        return $client->createDatabase("test_foobar");
+    }
+
+    /**
+     *  @expectedException RuntimeException
+     */
+    public function testCreateException()
+    {
+        $client = new Client;
+        return $client->createDatabase("test_foobar");
+    }
+}