How to write phpunit test in laravel for following function

public function storeAppUsePlaces($fromDate, $toDate) {
        $arrayData = $this->assignmentApplicationArr;
        DB::table('t_app_useplaces')->whereBetween('dtest_date', [$fromDate, $toDate])->delete(); 
        $arrayData = array_map(function($arrayData) {
            return array(
                'sexam_class' => $arrayData['exam_category'],
                'splace_code' => $arrayData['tc_code'],
                'sroom_code' => $arrayData['room_code'],
                'sroom_details_code' => $arrayData['room_detail_code'],
                'dtest_date' => $arrayData['test_date'],
                'stime_zone_class' => $arrayData['timezone'],
                'itotal_seats' => $arrayData['total_seats'],
                'itotal_applications' => $arrayData['total_applications'],
                'ireserve_count' => $arrayData['reserveCnt']
            );
        }, $arrayData);

        foreach ($arrayData as $key => $array_fam) {  
            $arrayData[$key]['idel_flg'] = 0;
            $arrayData[$key]['dcreate_date'] = date("Y-m-d");
            $arrayData[$key]['screate_name'] = 'app_allocation';
            $arrayData[$key]['dupdate_date'] = date("Y-m-d");
            $arrayData[$key]['supdate_name'] = '';
        }

        $items = collect($arrayData);
        $chunks = $items->chunk(ApplicationAllocationController::T_APP_USEPLACES_CHUNK_CNT);
        foreach ($chunks as $chunk) {
            DB::table('t_app_useplaces')->insert($chunk->toArray());
            return $chunks;
        }
    }

I already mock $arrayData = $this->assignmentApplicationArr; the array date like :

[0] => Array
        (
            [sexam_class] => 1
            [splace_code] => JT1841
            [sroom_code] => A1
            [sroom_details_code] => 01
            [dtest_date] => 2020-06-25
            [stime_zone_class] => 1
            [itotal_seats] => 20
            [itotal_applications] => 2
            [ireserve_count] => 2
            [idel_flg] => 0
            [dcreate_date] => 2020-08-17
            [screate_name] => app_allocation
            [dupdate_date] => 2020-08-17
            [supdate_name] =>
        )

but not understand how to write tests in PHPUnit in the Laravel framework for method storeAppUsePlaces. I'm new to PHPUnit and also new to Laravel. please, help me out.