PHPLIB-90: Client::__toString() should return connection URI

The legacy driver would return a comma-delimited list of host:port combinations; however, that would require __toString() to invoke topology discovery on new Manager instances. Returning the URI is less invasive.

src/Client.php

@@ -14,6 +14,7 @@ use MongoDB\Operation\ListDatabases;
 class Client
 {
     private $manager;
+    private $uri;
 
     /**
      * Constructs a new Client instance.
@@ -30,6 +31,17 @@ class Client
     public function __construct($uri, array $options = [], array $driverOptions = [])
     {
         $this->manager = new Manager($uri, $options, $driverOptions);
+        $this->uri = (string) $uri;
+    }
+
+    /**
+     * Return the connection string (i.e. URI).
+     *
+     * @param string
+     */
+    public function __toString()
+    {
+        return $this->uri;
     }
 
     /**

tests/ClientTest.php

+<?php
+
+namespace MongoDB\Tests;
+
+use MongoDB\Client;
+
+/**
+ * Unit tests for the Client class.
+ */
+class ClientTest extends TestCase
+{
+    public function testToString()
+    {
+        $client = new Client($this->getUri());
+
+        $this->assertSame($this->getUri(), (string) $client);
+    }
+}