diff --git a/tests/Composer/Test/Mock/ProcessExecutorMock.php b/tests/Composer/Test/Mock/ProcessExecutorMock.php
deleted file mode 100644
index 13ea9792b..000000000
--- a/tests/Composer/Test/Mock/ProcessExecutorMock.php
+++ /dev/null
@@ -1,31 +0,0 @@
-<?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\Mock;
-
-use Composer\Util\ProcessExecutor;
-
-class ProcessExecutorMock extends ProcessExecutor
-{
-    private $execute;
-
-    public function __construct(\Closure $execute)
-    {
-        $this->execute = $execute;
-    }
-
-    public function execute($command, &$output = null, $cwd = null)
-    {
-        $execute = $this->execute;
-
-        return $execute($command, $output, $cwd);
-    }
-}
diff --git a/tests/Composer/Test/Package/Loader/RootPackageLoaderTest.php b/tests/Composer/Test/Package/Loader/RootPackageLoaderTest.php
index fc3192414..2a4d9ccf6 100644
--- a/tests/Composer/Test/Package/Loader/RootPackageLoaderTest.php
+++ b/tests/Composer/Test/Package/Loader/RootPackageLoaderTest.php
@@ -15,7 +15,6 @@ namespace Composer\Test\Package\Loader;
 use Composer\Config;
 use Composer\Package\Loader\RootPackageLoader;
 use Composer\Package\BasePackage;
-use Composer\Test\Mock\ProcessExecutorMock;
 
 class RootPackageLoaderTest extends \PHPUnit_Framework_TestCase
 {
@@ -29,27 +28,39 @@ class RootPackageLoaderTest extends \PHPUnit_Framework_TestCase
 
         $manager = $this->getMockBuilder('\\Composer\\Repository\\RepositoryManager')
             ->disableOriginalConstructor()
-            ->getMock();
+            ->getMock()
+        ;
+
+        $executor = $this->getMockBuilder('\\Composer\\Util\\ProcessExecutor')
+            ->setMethods(array('execute'))
+            ->disableArgumentCloning()
+            ->disableOriginalConstructor()
+            ->getMock()
+        ;
+
+        $executor
+            ->expects($this->at(0))
+            ->method('execute')
+            ->with('git describe --exact-match --tags')
+            ->willReturn(1)
+        ;
 
         $self = $this;
 
-        /* Can do away with this mock object when https://github.com/sebastianbergmann/phpunit-mock-objects/issues/81 is fixed */
-        $processExecutor = new ProcessExecutorMock(function ($command, &$output = null, $cwd = null) use ($self, $commitHash) {
-            if (0 === strpos($command, 'git describe')) {
-                // simulate not being on a tag
-                return 1;
-            }
+        $executor
+            ->expects($this->at(1))
+            ->method('execute')
+            ->willReturnCallback(function ($command, &$output) use ($self, $commitHash) {
+                $self->assertEquals('git branch --no-color --no-abbrev -v', $command);
+                $output = "* (no branch) $commitHash Commit message\n";
 
-            $self->assertStringStartsWith('git branch', $command);
-
-            $output = "* (no branch) $commitHash Commit message\n";
-
-            return 0;
-        });
+                return 0;
+            })
+        ;
 
         $config = new Config;
         $config->merge(array('repositories' => array('packagist' => false)));
-        $loader = new RootPackageLoader($manager, $config, null, $processExecutor);
+        $loader = new RootPackageLoader($manager, $config, null, $executor);
         $package = $loader->load(array());
 
         $this->assertEquals("dev-$commitHash", $package->getVersion());
@@ -63,22 +74,32 @@ class RootPackageLoaderTest extends \PHPUnit_Framework_TestCase
 
         $manager = $this->getMockBuilder('\\Composer\\Repository\\RepositoryManager')
             ->disableOriginalConstructor()
-            ->getMock();
+            ->getMock()
+        ;
+
+        $executor = $this->getMockBuilder('\\Composer\\Util\\ProcessExecutor')
+            ->setMethods(array('execute'))
+            ->disableArgumentCloning()
+            ->disableOriginalConstructor()
+            ->getMock()
+        ;
 
         $self = $this;
 
-        /* Can do away with this mock object when https://github.com/sebastianbergmann/phpunit-mock-objects/issues/81 is fixed */
-        $processExecutor = new ProcessExecutorMock(function ($command, &$output = null, $cwd = null) use ($self) {
-            $self->assertEquals('git describe --exact-match --tags', $command);
+        $executor
+            ->expects($this->at(0))
+            ->method('execute')
+            ->willReturnCallback(function ($command, &$output) use ($self) {
+                $self->assertEquals('git describe --exact-match --tags', $command);
+                $output = "v2.0.5-alpha2";
 
-            $output = "v2.0.5-alpha2";
-
-            return 0;
-        });
+                return 0;
+            })
+        ;
 
         $config = new Config;
         $config->merge(array('repositories' => array('packagist' => false)));
-        $loader = new RootPackageLoader($manager, $config, null, $processExecutor);
+        $loader = new RootPackageLoader($manager, $config, null, $executor);
         $package = $loader->load(array());
 
         $this->assertEquals("2.0.5.0-alpha2", $package->getVersion());
@@ -92,26 +113,43 @@ class RootPackageLoaderTest extends \PHPUnit_Framework_TestCase
 
         $manager = $this->getMockBuilder('\\Composer\\Repository\\RepositoryManager')
             ->disableOriginalConstructor()
-            ->getMock();
+            ->getMock()
+        ;
+
+        $executor = $this->getMockBuilder('\\Composer\\Util\\ProcessExecutor')
+            ->setMethods(array('execute'))
+            ->disableArgumentCloning()
+            ->disableOriginalConstructor()
+            ->getMock()
+        ;
 
         $self = $this;
 
-        /* Can do away with this mock object when https://github.com/sebastianbergmann/phpunit-mock-objects/issues/81 is fixed */
-        $processExecutor = new ProcessExecutorMock(function ($command, &$output = null, $cwd = null) use ($self) {
-            if ('git describe --exact-match --tags' === $command) {
+        $executor
+            ->expects($this->at(0))
+            ->method('execute')
+            ->willReturnCallback(function ($command, &$output) use ($self) {
+                $self->assertEquals('git describe --exact-match --tags', $command);
                 $output = "foo-bar";
 
                 return 0;
-            }
+            })
+        ;
 
-            $output = "* foo 03a15d220da53c52eddd5f32ffca64a7b3801bea Commit message\n";
+        $executor
+            ->expects($this->at(1))
+            ->method('execute')
+            ->willReturnCallback(function ($command, &$output) use ($self) {
+                $self->assertEquals('git branch --no-color --no-abbrev -v', $command);
+                $output = "* foo 03a15d220da53c52eddd5f32ffca64a7b3801bea Commit message\n";
 
-            return 0;
-        });
+                return 0;
+            })
+        ;
 
         $config = new Config;
         $config->merge(array('repositories' => array('packagist' => false)));
-        $loader = new RootPackageLoader($manager, $config, null, $processExecutor);
+        $loader = new RootPackageLoader($manager, $config, null, $executor);
         $package = $loader->load(array());
 
         $this->assertEquals("dev-foo", $package->getVersion());
@@ -121,21 +159,25 @@ class RootPackageLoaderTest extends \PHPUnit_Framework_TestCase
     {
         $manager = $this->getMockBuilder('\\Composer\\Repository\\RepositoryManager')
             ->disableOriginalConstructor()
-            ->getMock();
+            ->getMock()
+        ;
 
-        $self = $this;
-
-        /* Can do away with this mock object when https://github.com/sebastianbergmann/phpunit-mock-objects/issues/81 is fixed */
-        $processExecutor = $this->getMockBuilder('Composer\Util\ProcessExecutor')
+        $executor = $this->getMockBuilder('\\Composer\\Util\\ProcessExecutor')
+            ->setMethods(array('execute'))
+            ->disableArgumentCloning()
             ->disableOriginalConstructor()
-            ->getMock();
-        $processExecutor->expects($this->any())
+            ->getMock()
+        ;
+
+        $executor
+            ->expects($this->any())
             ->method('execute')
-            ->willReturn(null);
+            ->willReturn(null)
+        ;
 
         $config = new Config;
         $config->merge(array('repositories' => array('packagist' => false)));
-        $loader = new RootPackageLoader($manager, $config, null, $processExecutor);
+        $loader = new RootPackageLoader($manager, $config, null, $executor);
         $package = $loader->load(array());
 
         $this->assertEquals("1.0.0.0", $package->getVersion());
@@ -148,10 +190,6 @@ class RootPackageLoaderTest extends \PHPUnit_Framework_TestCase
             ->disableOriginalConstructor()
             ->getMock();
 
-        $processExecutor = new ProcessExecutorMock(function ($command, &$output = null, $cwd = null) {
-            return 1;
-        });
-
         $config = new Config;
         $config->merge(array('repositories' => array('packagist' => false)));
 
@@ -188,32 +226,53 @@ class RootPackageLoaderTest extends \PHPUnit_Framework_TestCase
 
         $manager = $this->getMockBuilder('\\Composer\\Repository\\RepositoryManager')
             ->disableOriginalConstructor()
-            ->getMock();
+            ->getMock()
+        ;
+
+        $executor = $this->getMockBuilder('\\Composer\\Util\\ProcessExecutor')
+            ->setMethods(array('execute'))
+            ->disableArgumentCloning()
+            ->disableOriginalConstructor()
+            ->getMock()
+        ;
 
         $self = $this;
 
-        /* Can do away with this mock object when https://github.com/sebastianbergmann/phpunit-mock-objects/issues/81 is fixed */
-        $processExecutor = new ProcessExecutorMock(function ($command, &$output = null, $cwd = null) use ($self) {
-            if (0 === strpos($command, 'git rev-list')) {
+        $executor
+            ->expects($this->at(0))
+            ->method('execute')
+            ->willReturnCallback(function ($command) use ($self) {
+                $self->assertEquals('git describe --exact-match --tags', $command);
+
+                return 1;
+            })
+        ;
+
+        $executor
+            ->expects($this->at(1))
+            ->method('execute')
+            ->willReturnCallback(function ($command, &$output) use ($self) {
+                $self->assertEquals('git branch --no-color --no-abbrev -v', $command);
+                $output = "* latest-production 38137d2f6c70e775e137b2d8a7a7d3eaebf7c7e5 Commit message\n  master 4f6ed96b0bc363d2aa4404c3412de1c011f67c66 Commit message\n";
+
+                return 0;
+            })
+        ;
+
+        $executor
+            ->expects($this->at(2))
+            ->method('execute')
+            ->willReturnCallback(function ($command, &$output) use ($self) {
+                $self->assertEquals('git rev-list master..latest-production', $command);
                 $output = "";
 
                 return 0;
-            }
-
-            if ('git branch --no-color --no-abbrev -v' !== $command) {
-                return 1; //0;
-            }
-
-            $self->assertEquals('git branch --no-color --no-abbrev -v', $command);
-
-            $output = "* latest-production 38137d2f6c70e775e137b2d8a7a7d3eaebf7c7e5 Commit message\n  master 4f6ed96b0bc363d2aa4404c3412de1c011f67c66 Commit message\n";
-
-            return 0;
-        });
+            })
+        ;
 
         $config = new Config;
         $config->merge(array('repositories' => array('packagist' => false)));
-        $loader = new RootPackageLoader($manager, $config, null, $processExecutor);
+        $loader = new RootPackageLoader($manager, $config, null, $executor);
         $package = $loader->load(array('require' => array('foo/bar' => 'self.version')));
 
         $this->assertEquals("dev-master", $package->getPrettyVersion());
@@ -227,32 +286,42 @@ class RootPackageLoaderTest extends \PHPUnit_Framework_TestCase
 
         $manager = $this->getMockBuilder('\\Composer\\Repository\\RepositoryManager')
             ->disableOriginalConstructor()
-            ->getMock();
+            ->getMock()
+        ;
+
+        $executor = $this->getMockBuilder('\\Composer\\Util\\ProcessExecutor')
+            ->setMethods(array('execute'))
+            ->disableArgumentCloning()
+            ->disableOriginalConstructor()
+            ->getMock()
+        ;
 
         $self = $this;
 
-        /* Can do away with this mock object when https://github.com/sebastianbergmann/phpunit-mock-objects/issues/81 is fixed */
-        $processExecutor = new ProcessExecutorMock(function ($command, &$output = null, $cwd = null) use ($self) {
-            if (0 === strpos($command, 'git rev-list')) {
-                $output = "";
+        $executor
+            ->expects($this->at(0))
+            ->method('execute')
+            ->willReturnCallback(function ($command) use ($self) {
+                $self->assertEquals('git describe --exact-match --tags', $command);
+
+                return 1;
+            })
+        ;
+
+        $executor
+            ->expects($this->at(1))
+            ->method('execute')
+            ->willReturnCallback(function ($command, &$output) use ($self) {
+                $self->assertEquals('git branch --no-color --no-abbrev -v', $command);
+                $output = "* latest-production 38137d2f6c70e775e137b2d8a7a7d3eaebf7c7e5 Commit message\n  master 4f6ed96b0bc363d2aa4404c3412de1c011f67c66 Commit message\n";
 
                 return 0;
-            }
-
-            if ('git branch --no-color --no-abbrev -v' !== $command) {
-                return 1; //0;
-            }
-
-            $self->assertEquals('git branch --no-color --no-abbrev -v', $command);
-
-            $output = "* latest-production 38137d2f6c70e775e137b2d8a7a7d3eaebf7c7e5 Commit message\n  master 4f6ed96b0bc363d2aa4404c3412de1c011f67c66 Commit message\n";
-
-            return 0;
-        });
+            })
+        ;
 
         $config = new Config;
         $config->merge(array('repositories' => array('packagist' => false)));
-        $loader = new RootPackageLoader($manager, $config, null, $processExecutor);
+        $loader = new RootPackageLoader($manager, $config, null, $executor);
         $package = $loader->load(array('require' => array('foo/bar' => 'self.version'), "non-feature-branches" => array("latest-.*")));
 
         $this->assertEquals("dev-latest-production", $package->getPrettyVersion());