public function testScopeVariables()
 {
     $one = 'banana';
     $two = 123;
     $three = new \StdClass();
     $__psysh__ = 'ignore this';
     $_ = 'ignore this';
     $_e = 'ignore this';
     $shell = new Shell($this->getConfig());
     $shell->setScopeVariables(compact('one', 'two', 'three', '__psysh__', '_', '_e'));
     $this->assertNotContains('__psysh__', $shell->getScopeVariableNames());
     $this->assertEquals(array('one', 'two', 'three', '_'), $shell->getScopeVariableNames());
     $this->assertEquals('banana', $shell->getScopeVariable('one'));
     $this->assertEquals(123, $shell->getScopeVariable('two'));
     $this->assertSame($three, $shell->getScopeVariable('three'));
     $this->assertNull($shell->getScopeVariable('_'));
     $shell->setScopeVariables(array());
     $this->assertEquals(array('_'), $shell->getScopeVariableNames());
 }