diff --git a/tests/Composer/Test/Downloader/FossilDownloaderTest.php b/tests/Composer/Test/Downloader/FossilDownloaderTest.php
new file mode 100644
index 000000000..68babfd1d
--- /dev/null
+++ b/tests/Composer/Test/Downloader/FossilDownloaderTest.php
@@ -0,0 +1,173 @@
+<?php
+
+/*
+ * This file is part of Composer.
+ *
+ * (c) Nils Adermann <naderman@naderman.de>
+ *     Jordi Boggiano <j.boggiano@seld.be>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Composer\Test\Downloader;
+
+use Composer\Downloader\FossilDownloader;
+use Composer\TestCase;
+use Composer\Util\Filesystem;
+use Composer\Util\Platform;
+
+class FossilDownloaderTest extends TestCase
+{
+    /** @var string */
+    private $workingDir;
+
+    protected function setUp()
+    {
+        $this->workingDir = $this->getUniqueTmpDirectory();
+    }
+
+    protected function tearDown()
+    {
+        if (is_dir($this->workingDir)) {
+            $fs = new Filesystem;
+            $fs->removeDirectory($this->workingDir);
+        }
+    }
+
+    protected function getDownloaderMock($io = null, $config = null, $executor = null, $filesystem = null)
+    {
+        $io = $io ?: $this->getMock('Composer\IO\IOInterface');
+        $config = $config ?: $this->getMock('Composer\Config');
+        $executor = $executor ?: $this->getMock('Composer\Util\ProcessExecutor');
+        $filesystem = $filesystem ?: $this->getMock('Composer\Util\Filesystem');
+
+        return new FossilDownloader($io, $config, $executor, $filesystem);
+    }
+
+    /**
+     * @expectedException \InvalidArgumentException
+     */
+    public function testDownloadForPackageWithoutSourceReference()
+    {
+        $packageMock = $this->getMock('Composer\Package\PackageInterface');
+        $packageMock->expects($this->once())
+            ->method('getSourceReference')
+            ->will($this->returnValue(null));
+
+        $downloader = $this->getDownloaderMock();
+        $downloader->download($packageMock, '/path');
+    }
+
+    public function testDownload()
+    {
+        $packageMock = $this->getMock('Composer\Package\PackageInterface');
+        $packageMock->expects($this->any())
+            ->method('getSourceReference')
+            ->will($this->returnValue('trunk'));
+        $packageMock->expects($this->once())
+            ->method('getSourceUrls')
+            ->will($this->returnValue(array('http://fossil.kd2.org/kd2fw/')));
+        $processExecutor = $this->getMock('Composer\Util\ProcessExecutor');
+
+        $expectedFossilCommand = $this->getCmd('fossil clone \'http://fossil.kd2.org/kd2fw/\' \'repo.fossil\'');
+        $processExecutor->expects($this->at(0))
+            ->method('execute')
+            ->with($this->equalTo($expectedFossilCommand))
+            ->will($this->returnValue(0));
+
+        $expectedFossilCommand = $this->getCmd('fossil open \'repo.fossil\'');
+        $processExecutor->expects($this->at(1))
+            ->method('execute')
+            ->with($this->equalTo($expectedFossilCommand))
+            ->will($this->returnValue(0));
+
+        $expectedFossilCommand = $this->getCmd('fossil update \'trunk\'');
+        $processExecutor->expects($this->at(2))
+            ->method('execute')
+            ->with($this->equalTo($expectedFossilCommand))
+            ->will($this->returnValue(0));
+
+        $downloader = $this->getDownloaderMock(null, null, $processExecutor);
+        $downloader->download($packageMock, 'repo');
+    }
+
+    /**
+     * @expectedException \InvalidArgumentException
+     */
+    public function testUpdateforPackageWithoutSourceReference()
+    {
+        $initialPackageMock = $this->getMock('Composer\Package\PackageInterface');
+        $sourcePackageMock = $this->getMock('Composer\Package\PackageInterface');
+        $sourcePackageMock->expects($this->once())
+            ->method('getSourceReference')
+            ->will($this->returnValue(null));
+
+        $downloader = $this->getDownloaderMock();
+        $downloader->update($initialPackageMock, $sourcePackageMock, '/path');
+    }
+
+    public function testUpdate()
+    {
+        // Ensure file exists
+        $file = $this->workingDir . '/.fslckout';
+
+        if (!file_exists($file)) {
+            touch($file);
+        }
+
+        $packageMock = $this->getMock('Composer\Package\PackageInterface');
+        $packageMock->expects($this->any())
+            ->method('getSourceReference')
+            ->will($this->returnValue('trunk'));
+        $packageMock->expects($this->any())
+            ->method('getSourceUrls')
+            ->will($this->returnValue(array('http://fossil.kd2.org/kd2fw/')));
+        $processExecutor = $this->getMock('Composer\Util\ProcessExecutor');
+
+        $expectedFossilCommand = $this->getCmd("fossil changes");
+        $processExecutor->expects($this->at(0))
+            ->method('execute')
+            ->with($this->equalTo($expectedFossilCommand))
+            ->will($this->returnValue(0));
+        $expectedFossilCommand = $this->getCmd("fossil pull && fossil up 'trunk'");
+        $processExecutor->expects($this->at(1))
+            ->method('execute')
+            ->with($this->equalTo($expectedFossilCommand))
+            ->will($this->returnValue(0));
+
+        $downloader = $this->getDownloaderMock(null, null, $processExecutor);
+        $downloader->update($packageMock, $packageMock, $this->workingDir);
+    }
+
+    public function testRemove()
+    {
+        $expectedResetCommand = $this->getCmd('cd \'composerPath\' && fossil status');
+
+        $packageMock = $this->getMock('Composer\Package\PackageInterface');
+        $processExecutor = $this->getMock('Composer\Util\ProcessExecutor');
+        $processExecutor->expects($this->any())
+            ->method('execute')
+            ->with($this->equalTo($expectedResetCommand));
+        $filesystem = $this->getMock('Composer\Util\Filesystem');
+        $filesystem->expects($this->any())
+            ->method('removeDirectory')
+            ->with($this->equalTo('composerPath'))
+            ->will($this->returnValue(true));
+
+        $downloader = $this->getDownloaderMock(null, null, $processExecutor, $filesystem);
+        $downloader->remove($packageMock, 'composerPath');
+    }
+
+    public function testGetInstallationSource()
+    {
+        $downloader = $this->getDownloaderMock(null);
+
+        $this->assertEquals('source', $downloader->getInstallationSource());
+    }
+
+    private function getCmd($cmd)
+    {
+        return Platform::isWindows() ? strtr($cmd, "'", '"') : $cmd;
+    }
+}
diff --git a/tests/Composer/Test/Repository/Vcs/FossilDriverTest.php b/tests/Composer/Test/Repository/Vcs/FossilDriverTest.php
new file mode 100644
index 000000000..970abf34b
--- /dev/null
+++ b/tests/Composer/Test/Repository/Vcs/FossilDriverTest.php
@@ -0,0 +1,70 @@
+<?php
+
+/*
+ * This file is part of Composer.
+ *
+ * (c) Nils Adermann <naderman@naderman.de>
+ *     Jordi Boggiano <j.boggiano@seld.be>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Composer\Test\Repository\Vcs;
+
+use Composer\Repository\Vcs\FossilDriver;
+use Composer\Config;
+use Composer\TestCase;
+use Composer\Util\Filesystem;
+use Composer\Util\Platform;
+
+class FossilDriverTest extends TestCase
+{
+    protected $home;
+    protected $config;
+
+    public function setUp()
+    {
+        $this->home = $this->getUniqueTmpDirectory();
+        $this->config = new Config();
+        $this->config->merge(array(
+            'config' => array(
+                'home' => $this->home,
+            ),
+        ));
+    }
+
+    public function tearDown()
+    {
+        $fs = new Filesystem();
+        $fs->removeDirectory($this->home);
+    }
+
+    private function getCmd($cmd)
+    {
+        if (Platform::isWindows()) {
+            return strtr($cmd, "'", '"');
+        }
+
+        return $cmd;
+    }
+
+    public static function supportProvider()
+    {
+        return array(
+            array('http://fossil.kd2.org/kd2fw/', true),
+            array('https://chiselapp.com/user/rkeene/repository/flint/index', true),
+            array('ssh://fossil.kd2.org/kd2fw.fossil', true),
+        );
+    }
+
+    /**
+     * @dataProvider supportProvider
+     */
+    public function testSupport($url, $assertion)
+    {
+        $config = new Config();
+        $result = FossilDriver::supports($this->getMock('Composer\IO\IOInterface'), $config, $url);
+        $this->assertEquals($assertion, $result);
+    }
+}