Added tests for JSON errors, should help us figure out the cause of the problem in #11

lib/Json.php

@@ -0,0 +1,48 @@
+<?php
+/**
+ * PrivateBin
+ *
+ * a zero-knowledge paste bin
+ *
+ * @link      https://github.com/PrivateBin/PrivateBin
+ * @copyright 2012 Sébastien SAUVAGE (sebsauvage.net)
+ * @license   https://www.opensource.org/licenses/zlib-license.php The zlib/libpng License
+ * @version   0.22
+ */
+
+namespace PrivateBin;
+
+use Exception;
+
+/**
+ * Json
+ *
+ * Provides JSON functions in an object oriented way.
+ */
+class Json
+{
+    /**
+     * Returns a string containing the JSON representation of the given input
+     *
+     * @access public
+     * @static
+     * @param  mixed $input
+     * @throws Exception
+     * @return string
+     */
+    public static function encode($input)
+    {
+        $jsonString = json_encode($input);
+        $errorCode = json_last_error();
+        if ($errorCode === JSON_ERROR_NONE) {
+            return $jsonString;
+        }
+
+        $message = 'A JSON error occurred';
+        if (function_exists('json_last_error_msg')) {
+            $message .= ': ' . json_last_error_msg();
+        }
+        $message .= ' (' . $errorCode . ')';
+        throw new Exception($message, 90);
+    }
+}