How to get get page source in codeception yii 2 - unit-testing

Question

I need save the source code of failed test to fix it. How to get the source html while using codeception test in yii 2?
I cannot get $I->grabPageSource() and $I->_getResponseContent() to work though there are these exact functions.
public function checkCall(FunctionalTester $I)
{
$I->amOnRoute('mx/ed',['model' => 'State']);
$I->seeResponseCodeIs(200);
$I->seeResponseCodeIsSuccessful();
$html = $I->grabPageSource();
}

Answer 1

Codeception saves page source of last request for all failed tests in tests/_output directory by itself, there is nothing for you to do.
Failed assertion throws exception so your code after $I->seeResponseCodeIsSuccessful is not executed.
If you want to implement some custom error handling in specific test, you can wrap assertions in try-catch block and grabPageSource inside catch.
public function checkCall(FunctionalTester $I)
{
$I->amOnRoute('mx/ed',['model' => 'State']);
try{
$I->seeResponseCodeIs(200);
$I->seeResponseCodeIsSuccessful();
} catch (Exception $e) {
$html = $I->grabPageSource();
//do your error handling here
throw $e; //rethrow exception to make test fail
}
}
If you want to implement custom error handling for all tests, add _failed method to Helper\Functional class in tests/_support/Helper directory.
public function _failed(\Codeception\TestInterface $test, $fail)
{
$testName = $test->getMetadata()->getName();
$pageSource = $this->getModule('Yii2')->getPageSource();
//do your error handling here
}