diff --git a/tests/Composer/Test/Package/Version/VersionGuesserTest.php b/tests/Composer/Test/Package/Version/VersionGuesserTest.php
index cf5377670..3e37e67c1 100644
--- a/tests/Composer/Test/Package/Version/VersionGuesserTest.php
+++ b/tests/Composer/Test/Package/Version/VersionGuesserTest.php
@@ -158,16 +158,15 @@ class VersionGuesserTest extends \PHPUnit_Framework_TestCase
         $this->assertEquals("dev-$commitHash", $versionData['version']);
     }
 
-    public function testDetachedHeadBecomesDevHashGit2()
+    public function testDetachedFetchHeadBecomesDevHashGit2()
     {
-        $commitHash = '03a15d220da53c52eddd5f32ffca64a7b3801bea';
+        $commitHash = 'da53c52eddd5f32ffca64a7b3801bea';
 
         $executor = $this->getMockBuilder('\\Composer\\Util\\ProcessExecutor')
-            ->setMethods(array('execute'))
+            ->setMethods(['execute'])
             ->disableArgumentCloning()
             ->disableOriginalConstructor()
-            ->getMock()
-        ;
+            ->getMock();
 
         $self = $this;
 
@@ -176,16 +175,45 @@ class VersionGuesserTest extends \PHPUnit_Framework_TestCase
             ->method('execute')
             ->willReturnCallback(function ($command, &$output) use ($self, $commitHash) {
                 $self->assertEquals('git branch --no-color --no-abbrev -v', $command);
-                $output = "* (HEAD detached at " . substr($commitHash, 0, 9) . ") $commitHash Commit message\n";
+                $output = "* (HEAD detached at FETCH_HEAD) $commitHash Commit message\n";
 
                 return 0;
-            })
-        ;
+            });
 
         $config = new Config;
-        $config->merge(array('repositories' => array('packagist' => false)));
+        $config->merge(['repositories' => ['packagist' => false]]);
         $guesser = new VersionGuesser($config, $executor, new VersionParser());
-        $versionData = $guesser->guessVersion(array(), 'dummy/path');
+        $versionData = $guesser->guessVersion([], 'dummy/path');
+
+        $this->assertEquals("dev-$commitHash", $versionData['version']);
+    }
+
+    public function testDetachedCommitHeadBecomesDevHashGit2()
+    {
+        $commitHash = 'da53c52eddd5f32ffca64a7b3801bea';
+
+        $executor = $this->getMockBuilder('\\Composer\\Util\\ProcessExecutor')
+            ->setMethods(['execute'])
+            ->disableArgumentCloning()
+            ->disableOriginalConstructor()
+            ->getMock();
+
+        $self = $this;
+
+        $executor
+            ->expects($this->at(0))
+            ->method('execute')
+            ->willReturnCallback(function ($command, &$output) use ($self, $commitHash) {
+                $self->assertEquals('git branch --no-color --no-abbrev -v', $command);
+                $output = "* (HEAD detached at da53c52ed) $commitHash Commit message\n";
+
+                return 0;
+            });
+
+        $config = new Config;
+        $config->merge(['repositories' => ['packagist' => false]]);
+        $guesser = new VersionGuesser($config, $executor, new VersionParser());
+        $versionData = $guesser->guessVersion([], 'dummy/path');
 
         $this->assertEquals("dev-$commitHash", $versionData['version']);
     }