@lonnieezell @jim-parry, I am trying to write the test case for the private method castAsJson() of Entity Class.
Below is my code for the test scenario.

public function testCastAsJSONSyntaxError()
{
	$entity = new Entity();
	$method = $this->getPrivateMethodInvoker($entity,'castAsJson');
		
	$this->expectException(CastException::class);
	$this->expectExceptionMessage('Syntax error, malformed JSON');

	$method("'{ bar: \"baz\" }'", true);
}

At the time of build, I am getting error like,

1) CodeIgniter\EntityTest::testCastAsJSONSyntaxError
Failed asserting that exception of type "CodeIgniter\Exceptions\CastException" is thrown.

Could you please help me out with this. So I will be able to generate test scenarios.

It looks like you are trying to json_decode a JSON string and expecting that to trigger an exception. That doesn't sound right.
Wouldn't you want to give the method something that can't be json_decoded? eg "( this is bad"

Thanks. It is working.

Yes, it is reasonable.
Normally, however, you would thoroughly test on your system before pushing (and ending up with a bunch of commits), rather than using travis-ci to see if they work. Do you have the unit tests running on your system?

I have tried but the system is not able to configure XDebug. I have tried many times but no success.
Also, I do not have Postgre, so all the test scenarios of it give an error.