Add possibility to use custom consumer

.gitignore

@@ -4,3 +4,4 @@ composer.phar
 test/analytics.log
 /.vscode
 .phplint-cache
+/.idea

lib/Segment/Client.php

@@ -21,17 +21,26 @@ class Segment_Client {
    *
    */
   public function __construct($secret, $options = array()) {
+
     $consumers = array(
-      "socket"     => "Segment_Consumer_Socket",
-      "file"       => "Segment_Consumer_File",
-      "fork_curl"  => "Segment_Consumer_ForkCurl",
-      "lib_curl"   => "Segment_Consumer_LibCurl"
+        "socket"     => "Segment_Consumer_Socket",
+        "file"       => "Segment_Consumer_File",
+        "fork_curl"  => "Segment_Consumer_ForkCurl",
+        "lib_curl"   => "Segment_Consumer_LibCurl"
     );
-
     // Use our socket libcurl by default
     $consumer_type = isset($options["consumer"]) ? $options["consumer"] :
                                                    "lib_curl";
 
+    if (!array_key_exists($consumer_type, $consumers) && class_exists($consumer_type)) {
+        if (!is_subclass_of($consumer_type, Segment_Consumer::class)) {
+            throw new Exception('Consumers must extend the Segment_Consumer abstract class');
+        }
+        // Try to resolve it by class name
+        $this->consumer  = new $consumer_type($secret, $options);
+        return;
+    }
+
     $Consumer = $consumers[$consumer_type];
 
     $this->consumer = new $Consumer($secret, $options);
@@ -131,6 +140,14 @@ public function flush() {
     return true;
   }
 
+    /**
+     * @return Segment_Consumer
+     */
+    public function getConsumer() {
+      return $this->consumer;
+    }
+
+
   /**
    * Formats a timestamp by making sure it is set
    * and converting it to iso8601.

test/ClientTest.php

@@ -0,0 +1,31 @@
+<?php
+
+require_once __DIR__ . '/../lib/Segment/Client.php';
+
+class ClientTest extends PHPUnit_Framework_TestCase
+{
+    /** @test */
+    public function it_uses_the_lib_curl_consumer_as_default()
+    {
+        $client = new Segment_Client('foobar', []);
+        $this->assertInstanceOf(Segment_Consumer_LibCurl::class, $client->getConsumer());
+    }
+
+    /** @test */
+    public function can_provide_the_consumer_configuration_as_string()
+    {
+        $client = new Segment_Client('foobar', [
+            'consumer' => 'fork_curl',
+        ]);
+        $this->assertInstanceOf(Segment_Consumer_ForkCurl::class, $client->getConsumer());
+    }
+
+    /** @test */
+    public function can_provide_a_class_namespace_as_consumer_configuration()
+    {
+        $client = new Segment_Client('foobar', [
+            'consumer' => Segment_Consumer_ForkCurl::class,
+        ]);
+        $this->assertInstanceOf(Segment_Consumer_ForkCurl::class, $client->getConsumer());
+    }
+}