public function testCompileIsNull()
 {
     $c = new BaseCompiler();
     $where = ['type' => 'Null', 'table' => '', 'cols' => ['author_id'], 'val' => null, 'logic' => 'AND', 'not' => false];
     //$where = new SimpleCond('a', 'author_id', '=', 12);
     $components['where'] = array($where);
     $expected = 'WHERE `author_id` IS NULL';
     $result = $c->compileWhere($components);
     $this->assertEquals($expected, $result);
     $where = ['type' => 'Null', 'table' => '', 'cols' => ['author_id'], 'val' => null, 'logic' => 'AND', 'not' => true];
     //$where = new SimpleCond('a', 'author_id', '=', 12);
     //$where = new SimpleCond('a', 'author_id', '=', 12);
     $components['where'] = array($where);
     $expected = 'WHERE `author_id` IS NOT NULL';
     $result = $c->compileWhere($components);
     $this->assertEquals($expected, $result);
 }