think\Template::assign PHP Method

    public function assign($name, $value = '')
    {
        if (is_array($name)) {
            $this->data = array_merge($this->data, $name);
        } else {
            $this->data[$name] = $value;
        }
    }

 public function testVarGet()
 {
     $template = new Template();
     $data = ['a' => 'a', 'b' => 'b'];
     $template->assign($data);
     $this->assertEquals($data, $template->get());
 }