I think that the best way to compare if 2 variables contain the same test is to compare results of \Codeception\Test\Descriptor::getTestSignatureUnique().

if ($lastFailure && Descriptor::getTestSignatureUnique($lastFailure->getTest()) === Descriptor::getTestSignatureUnique($this)

For ideas how to implement test for your change see

	public function testsWithConditionalFails(CliGuy $I)
	{
	$I->executeCommand('run scenario ConditionalCept --no-exit');
	$I->seeInShellOutput('There were 3 failures');
	$I->seeInShellOutput('Fail File "not-a-file" not found');
	$I->seeInShellOutput('Fail File "not-a-dir" not found');
	$I->seeInShellOutput('Fail File "nothing" not found');
	}

	public function runTestWithAnnotationDataprovider(CliGuy $I)
	{
	$I->executeCommand('run scenario -g dataprovider --steps');
	$I->seeInShellOutput('OK (18 tests');
	}

	public function runFailedTestAndCheckOutput(CliGuy $I)
	{
	$I->executeCommand('run scenario FailedCept', false);
	$testPath = implode(DIRECTORY_SEPARATOR, ['tests', 'scenario', 'FailedCept.php']);
	$I->seeInShellOutput('1) FailedCept: Fail when file is not found');
	$I->seeInShellOutput('Test ' . $testPath);
	$I->seeInShellOutput('Step See file found "games.zip"');
	$I->seeInShellOutput('Fail File "games.zip" not found at ""');
	}

	public function runTestWithCustomSetupMethod(CliGuy $I)
	{
	$I->executeCommand('run powers PowerUpCest');
	$I->dontSeeInShellOutput('FAILURES');
	}

	public function runCestWithTwoFailedTest(CliGuy $I)
	{
	$I->executeCommand('run scenario PartialFailedCest', false);
	$I->seeInShellOutput('See file found "testcasetwo.txt"');
	$I->seeInShellOutput('See file found "testcasethree.txt"');
	$I->seeInShellOutput('Tests: 3,');
	$I->seeInShellOutput('Failures: 2.');
	}

	public function failedTestFollowedByExceptionReportsCorrectStep(CliGuy $I)
	{
	$I->executeCommand('run scenario FailureAndExceptionCest', false);
	$I->seeInShellOutput('1. $I->throwException("test exception")');
	$I->seeInShellOutput('Step Assert same 1,2');
	$I->seeInShellOutput('Failed asserting that 2 is identical to 1.');
	}

	public function displaysAllFailedConditionalStepsInOneCest(CliGuy $I)
	{
	$I->executeCommand('run scenario MultipleConditionalFailsCest --no-ansi', false);
	$I->seeInShellOutput('x MultipleConditionalFailsCest: Multiple fails 3x[F]');
	$I->dontSeeInShellOutput('MultipleConditionalFailsCest: Multiple fails 2x[F]');
	$I->dontSeeInShellOutput('MultipleConditionalFailsCest: Multiple fails [F]');
	$I->dontSeeInShellOutput('MultipleConditionalFailsCest: Multiple fails[F]');
	$I->seeInShellOutput('There were 3 failures:');
	$I->seeInShellOutput('Step Can see file found "not-a-file"');
	$I->seeInShellOutput('Step Can see file found "not-a-dir"');
	$I->seeInShellOutput('Step Can see file found "nothing"');
	$filename = implode(DIRECTORY_SEPARATOR, ['tests', 'scenario','MultipleConditionalFailsCest.php']);
	$I->seeInShellOutput(' 1. $I->canSeeFileFound("not-a-file") at ' . $filename . ':7');
	$I->seeInShellOutput(' 7. $I->canSeeFileFound("not-a-dir") at ' . $filename . ':13');
	$I->seeInShellOutput(' 13. $I->canSeeFileFound("nothing") at ' . $filename . ':19');
	}

	public function checkForFails(CliGuy $I)
	{
	$I->amInPath('tests/data/sandbox');
	$I->executeCommand('run order FailedCept.php --no-exit');
	$I->seeFileFound('order.txt', 'tests/_output');
	$I->expect('global bootstrap, initialization, beforeSuite, before, bootstrap, test, fail, after, afterSuite');
	$I->seeFileContentsEqual("BIB([STF])");
	}

	public function checkForCanCantFails(CliGuy $I)
	{
	$I->amInPath('tests/data/sandbox');
	$I->executeCommand('run order CanCantFailCept.php --no-exit');
	$I->seeFileFound('order.txt', 'tests/_output');
	$I->expect(
	'global bootstrap, initialization, beforeSuite, before, bootstrap, test,'
	. ' test, fail, after, afterSuite'
	);
	$I->seeFileContentsEqual("BIB([STTF])");
	}

	public function checkForCanCantFailsInCest(CliGuy $I)
	{
	$I->amInPath('tests/data/sandbox');
	$I->executeCommand('run order CanCantFailCest.php --no-ansi --no-exit');
	$I->seeInShellOutput('x CanCantFailCest: Test one [F]');
	$I->seeInShellOutput('x CanCantFailCest: Test two [F]');
	$I->dontSeeInShellOutput('+ CanCantFailCest: One');
	$I->dontSeeInShellOutput('+ CanCantFailCest: Two');
	$I->seeFileFound('order.txt', 'tests/_output');
	$I->expect(
	'global bootstrap, initialization, beforeSuite, before, bootstrap, test,'
	. ' test, fail, test, test, fail, after, afterSuite'
	);
	$I->seeFileContentsEqual("BIB([TTF][TTF])");
	}

	public function checkForCanCantFailsInTest(CliGuy $I)
	{
	$I->amInPath('tests/data/sandbox');
	$I->executeCommand('run order CanCantFailTest.php --no-ansi --no-exit');
	$I->seeInShellOutput('x CanCantFailTest: One');
	$I->seeInShellOutput('x CanCantFailTest: Two');
	$I->dontSeeInShellOutput('+ CanCantFailTest: One');
	$I->dontSeeInShellOutput('+ CanCantFailTest: Two');
	$I->seeFileFound('order.txt', 'tests/_output');
	$I->expect(
	'global bootstrap, initialization, beforeSuite, before, bootstrap, test,'
	. ' test, fail, test, test, fail, after, afterSuite'
	);
	$I->seeFileContentsEqual("BIB([TTF][TTF])");
	}

	public function checkSimpleFiles(CliGuy $I)
	{
	$I->amInPath('tests/data/sandbox');
	$I->executeCommand('run order --no-exit --group simple');
	$I->seeFileFound('order.txt', 'tests/_output');
	$I->seeFileContentsEqual("BIBP([ST][STTF][STF][ST])");
	}

contains some similar tests too, but they are more difficult to understand.