function testListSymbols() { $this->assertEquals(array(), array_diff(array('abc', 'def', 'ghi'), $this->scope->listSymbols())); $scope = new Lisphp_Scope($this->scope); $scope->let('jkl', 123); $scope->let('abc', 456); $this->assertEquals(array(), array_diff(array('def', 'ghi', 'jkl', 'abc'), $scope->listSymbols())); }