Removed extra slash after enterprise URL

This will fix #511

Author: Nyholm

lib/Github/Client.php

@@ -315,7 +315,7 @@ private function setEnterpriseUrl($enterpriseUrl)
         $builder->removePlugin(PathPrepend::class);
 
         $builder->addPlugin(new Plugin\AddHostPlugin(UriFactoryDiscovery::find()->createUri($enterpriseUrl)));
-        $builder->addPlugin(new PathPrepend(sprintf('/api/%s/', $this->getApiVersion())));
+        $builder->addPlugin(new PathPrepend(sprintf('/api/%s', $this->getApiVersion())));
     }
 
     /**

test/Github/Tests/ClientTest.php

@@ -7,7 +7,10 @@
 use Github\Exception\BadMethodCallException;
 use Github\HttpClient\Builder;
 use Github\HttpClient\Plugin\Authentication;
+use GuzzleHttp\Psr7\Response;
 use Http\Client\Common\Plugin;
+use Http\Client\HttpClient;
+use Psr\Http\Message\RequestInterface;
 
 class ClientTest extends \PHPUnit_Framework_TestCase
 {
@@ -205,4 +208,25 @@ public function getApiClassesProvider()
             array('meta', Api\Meta::class)
         );
     }
+
+    /**
+     * Make sure that the URL is correct when using enterprise.
+     */
+    public function testEnterpriseUrl()
+    {
+        $httpClientMock = $this->getMockBuilder(HttpClient::class)
+            ->setMethods(['sendRequest'])
+            ->getMock();
+
+        $httpClientMock->expects($this->once())
+            ->method('sendRequest')
+            ->with($this->callback(function(RequestInterface $request) {
+                return (string) $request->getUri() === 'https://foobar.com/api/v3/enterprise/stats/all';
+            }))
+            ->willReturn(new Response(200, [], '[]'));
+
+        $httpClientBuilder = new Builder($httpClientMock);
+        $client = new Client($httpClientBuilder, null, 'https://foobar.com');
+        $client->enterprise()->stats()->show('all');
+    }
 }