diff --git a/spec/GrumPHP/Locator/ChangedFilesSpec.php b/spec/GrumPHP/Locator/ChangedFilesSpec.php
index 0f2d5531d..5077825a9 100644
--- a/spec/GrumPHP/Locator/ChangedFilesSpec.php
+++ b/spec/GrumPHP/Locator/ChangedFilesSpec.php
@@ -4,6 +4,7 @@
 
 use Gitonomy\Git\Diff\Diff;
 use Gitonomy\Git\Diff\File;
+use Gitonomy\Git\WorkingCopy;
 use Gitonomy\Git\Repository;
 use PhpSpec\ObjectBehavior;
 use Prophecy\Argument;
@@ -37,13 +38,14 @@ protected function mockFile($name, $isRename = false, $isDelete = false)
         return $file->reveal();
     }
 
-    function it_will_list_all_diffed_files(Repository $repository, Diff $diff)
+    function it_will_list_all_diffed_files(Repository $repository, Diff $diff, WorkingCopy $workingCopy)
     {
         $changedFile = $this->mockFile('file1.txt');
         $movedFile = $this->mockFile('file2.txt', true);
         $deletedFile = $this->mockFile('file3.txt', false, true);
 
-        $repository->getDiff('HEAD')->willReturn($diff);
+        $repository->getWorkingCopy()->willReturn($workingCopy);
+        $workingCopy->getDiffStaged()->willReturn($diff);
         $diff->getFiles()->willReturn(array($changedFile, $movedFile, $deletedFile));
 
         $result = $this->locate();
diff --git a/src/GrumPHP/Locator/ChangedFiles.php b/src/GrumPHP/Locator/ChangedFiles.php
index 6821cada3..bb046fcfb 100644
--- a/src/GrumPHP/Locator/ChangedFiles.php
+++ b/src/GrumPHP/Locator/ChangedFiles.php
@@ -34,7 +34,7 @@ public function __construct(Repository $repository)
      */
     public function locate()
     {
-        $diff = $this->repository->getDiff('HEAD');
+        $diff = $this->repository->getWorkingCopy()->getDiffStaged();
         $files = array();
         /** @var File $file */
         foreach ($diff->getFiles() as $file) {