Post request for CI4 Unit testing - codeigniter

Question

I have the following code running in CI 4.1.2:
public function testForgotten(){
fwrite(STDERR,"\n\nProcess Forgotten:\n");
$_COOKIE[csrf_token()] = csrf_hash();
$result = $this->post('site/forgotten',array(
'Username' => 'my#email.com',
csrf_token() => csrf_hash(),
));
print'<pre>';print_r($result->response());print'</pre>';
$result->assertRedirect();
}
As you can see I simply want to check if the forgotten password form/page is working. However the output of $result->response() includes the unposted to page along with <form action="http://example.com/site/forgotten" id="Config\Forms::reset" enctype="multipart/form-data" method="post" accept-charset="utf-8"> as part of the form (noting I've not put in the example.com - Codeigniter did that! So just wondering what I'm missing in terms of getting this test to run/work?
FYI I'm running under a PHAR file with php punit.phar tests/app/Controllers/SiteTests.php which works fine when running simple get('/path/to/page'); calls.
I have since found the example.com can be changed in phpunit.xml.dist but this has still not fixed the assertRedirect issue.

Answer 1

So the answer appears to be that CI4 does not actually populate the $_GET or $_POST variables rather its own internal mechanism. This becomes apparent when you use:
$request = \Config\Services::request();
print_r($request->getPost('Username'));
Instead of $_POST.
The solution is either a) use the getPost() type functions or b) amend the framework (yes shock/horror!) in system/HTTP/RequestTrait.php and setGlobal to include:
switch ($method){
case 'post': $_POST = $value; break;
case 'get': $_GET = $value; break;
}

Answer 2

It is a working solution for Testing Controllers ONLY. Not for HTTP Testing.
Your code can be rewritten as:
/**
* #throws \Exception
*/
public function testForgotten()
{
fwrite(STDERR, "\n\nProcess Forgotten:\n");
$_COOKIE[csrf_token()] = csrf_hash();
$request = $this->request
->withMethod('post')
// parameter 'post' for post method parameters
->setGlobal('post', [
'Username' => 'my#email.com',
csrf_token() => csrf_hash()
]);
$result = $this
->withRequest($request)
->controller(YourSiteController::class)
->execute('forgotten');
print'<pre>';
print_r($result->response());
print'</pre>';
$result->assertRedirect();
}
Key-points to note:
Use $request = $this->request;, then chain it by withMethod() and setGlobal() for adapting POST request method and accepting POST request parameters;
Bind the $request variable by $this->withRequest($request);
Chain $this->withRequest($request) by controller() and execute() to get the result.