From 8662b58d676b1a74eaa6bdc34c98f6d488eaf783 Mon Sep 17 00:00:00 2001
From: Andrey Kutejko <andy128k@gmail.com>
Date: Fri, 2 Jan 2015 18:03:15 +0200
Subject: [PATCH] collection inits utility

---
 src/collection.php   | 14 ++++++++++++++
 t/CollectionTest.php | 15 +++++++++++++++
 2 files changed, 29 insertions(+)

diff --git a/src/collection.php b/src/collection.php
index d9b39ae..11b31e1 100644
--- a/src/collection.php
+++ b/src/collection.php
@@ -91,5 +91,19 @@ final class Collection
         }
         return $groups;
     }
+
+    public static function inits($collection)
+    {
+        $result = array();
+        $init = array();
+
+        $result[] = $init;
+        foreach ($collection as $item) {
+            $init = array_merge($init, array($item));
+            $result[] = $init;
+        }
+
+        return $result;
+    }
 }
 
diff --git a/t/CollectionTest.php b/t/CollectionTest.php
index a1c505e..24db627 100644
--- a/t/CollectionTest.php
+++ b/t/CollectionTest.php
@@ -58,5 +58,20 @@ class CollectionTest extends PHPUnit_Framework_TestCase
         $this->assertEquals(2, count($groups['red']));
         $this->assertEquals(2, count($groups['green']));
     }
+
+    public function testInits()
+    {
+        $this->assertEquals(array(array()),
+            \PFF\Collection::inits(array()));
+
+        $this->assertEquals(array(array(), array('1')),
+            \PFF\Collection::inits(array('1')));
+
+        $this->assertEquals(array(array(), array('1'), array('1', 2)),
+            \PFF\Collection::inits(array('1', 2)));
+
+        $this->assertEquals(array(array(), array(1), array(1, '2'), array(1, '2', 3)),
+            \PFF\Collection::inits(array(1, '2', 3)));
+    }
 }
 
-- 
2.49.0