/**
  * @covers WindowsAzure\Common\CloudConfigurationManager::unregisterSource
  * @covers WindowsAzure\Common\CloudConfigurationManager::_init
  */
 public function testUnRegisterSourceWithDefaultSource()
 {
     // Setup
     $expectedKey = $this->_key;
     $expectedValue = $this->_value . "extravalue4";
     $name = 'my_source';
     CloudConfigurationManager::registerSource($name, function ($key) use($expectedKey, $expectedValue) {
         if ($key == $expectedKey) {
             return $expectedValue;
         }
     });
     // Test
     $callback = CloudConfigurationManager::unregisterSource(ConnectionStringSource::ENVIRONMENT_SOURCE);
     // Assert
     $actual = CloudConfigurationManager::getConnectionString($expectedKey);
     $this->assertEquals($expectedValue, $actual);
     $this->assertNotNull($callback);
 }