unit test case error on container

[Thejaswini-Rao-U]

i m trying to write unit test cases for the current project service methods, getting error as attached below

i have called current method as below

use ExportBundle\Service\ExportService;

class ExportServiceTest extends \Codeception\Test\Unit
{

// tests
public function testGenerateProductCsv()
{
$this->exportService = new ExportService();
$this->exportService->generateProductCsv();
}
}

using codeception version is 2.4
and php v is 7.3

can anyone please help me to solve this issue

Thanks in advance

[Naktibalda]

Error happens in Pimcore.php , right?
This is not a Codeception issue.

[Thejaswini-Rao-U]

@Naktibalda , thanks for the response

but when we run the function, its executing on website or backend

but when we call using test cases, gets error, i have included all the namespaces needed, im not coming to know why this error arrises?

can please tell me how to correct it if im doing anything wrong in the writing test cases?

method below

// tests
// tests
public function testGenerateProductCsv()

{
    $this->exportService = new ExportService();
    $this->exportService->generateProductCsv();
}

**generateProductCsv** => method name im calling here in test file. (actual file name where method exists is **ExportService.php**

my file name is **ExportServiceTest.php** 

thanks in advance