public function testParams()
 {
     Params::setParams([1, 2, 3]);
     $this->assertEquals([1, 2, 3], Params::getParams());
     Params::setParams(['a' => ['b' => 1]]);
     $this->assertEquals(1, Params::get('a.b'));
     $this->assertEquals(1, Params::get('a.c', 1));
     $this->assertEquals(1, Params::get('a.b.c', 1));
     $this->assertEquals(null, Params::get('abc'));
 }