GitHub CI - move a file using PHP copy() in a PHPUnit test - php

Question

I have an application written in PHP 8. I've added some Unit Tests for it using PHPUnit.
In one of the tests I am using PHP's copy function to move a file from one location to another. This is done to test an endpoint which downloads the file by moving a "dummy" file to the "real" location that the file would be in, in the production application.
My test looks like this:
// tests/TestCase/Controller/DocsControllerTest.php
public function testDownload()
{
$testFile = '75e57e4a-2149-4270-9d76-c7c8f0298c2c.pdf';
copy('/full/path/to/testFiles/' . $testFile, '/webroot/docs/');
// Download the file from the endpoint
$id = 9; // File ID to download
$this->get('/download/' . $id);
// This should return a HTTP 200 response containing the PDF
$this->assertResponseCode(200, 'Downloading a valid PDF should produce a 200 response.');
}
To explain the function above:
We have a test file called 75e57e4a-2149-4270-9d76-c7c8f0298c2c.pdf. This is a real PDF file with appropriate encoding.
We move the file, using copy(), from a directory where we hold some test files, into the full directory path where the production web application will really store the files (/webroot/docs/).
The remainder of the logic deals with downloading the file from the endpoint. The $this->get makes a HTTP GET request to an endpoint (/download/) which also passes in the appropriate file ID. The location of the file is looked up from a MySQL database and then is streamed to the browser, thus generating a HTTP 200 response containing the PDF.
This works both when I run phpunit locally by executing vendor/bin/phpunit --filter testDownload:
PHPUnit 9.5.10 by Sebastian Bergmann and contributors.
Time: 00:05.053, Memory: 20.00 MB
OK (1 test, 16 assertions)
It also works in a browser, i.e. if I make a request to /download/9 I am served the appropriate PDF.
The problem I'm having is on GitHub. When I run the unit test there it fails the CI with this error:
Warning Error: copy(/home/runner/work/my-app/webroot/docs/75e57e4a-2149-4270-9d76-c7c8f0298c2c.pdf): Failed to open stream: No such file or directory
In [/home/runner/work/my-app/tests/TestCase/Controller/DocsControllerTest.php, line 745]
Given that this works locally I can't understand why this error is occurring. Is there some restriction with using copy() in GitHub's CI?
The directory and files at /full/path/to/testFiles/ are not .gitignore'd so they are committed with the rest of the repo code. So the test file, 75e57e4a-2149-4270-9d76-c7c8f0298c2c.pdf, exists within the codebase on GitHub.
I am using PHPUnit 9.5.10, PHP 8.0 on a Mac running macOS Monterey (12.2).

Answer 1

It clearly reads:
Failed to open stream: No such file or directory
Maybe add .gitkeep into target directory docs? It may also be, that the source file is not there. One usually can take this error message literal. While it's entirely unclear what $this->get() even is or why your Mac would have anything to do with running GitHub Action?