How to verify that the File Explorer is opened?

Im learning Java Automation using Selenium.

Im currently working on a test that checks simple file upload and verifies that the file was Indeed uploaded

Heres the test:

    @Test
public void checkFileUploadProcess() {
    SoftAssertions soft = new SoftAssertions();
    BaseOperations.navigateTo(URLs.FORMS_PAGE);
    SingleFileUpload page = new SingleFileUpload(getDriver());

    page.fileUpload(Files.FILE_3);
    log.debug(page.getUploadCVStateValue());
    soft.assertThat(page.getUploadCVStateValue().isEmpty()).isFalse();
    soft.assertAll();
}

It has a few methods that Ive created in order to convey common actions (locating an element / label, getting their attribute values, opening a Web Page, creating a ThreadLocal WebDriver instance, waits, etc...)

Below I will post only methods that played a key role in it

Here they are:

1. File Upload method / retrieving FilePath String value:

     public void fileUpload(Files filename) {
        String fullPath = getFilePath(filename);
        WebElement input = getUploadCVElement();
        log.debug(fullPath);

        input.sendKeys(fullPath);
    }

    public String getFilePath(Files filename) {
        String fileName = Files.getFileName(filename.name());
        return String.format(Constants.BASE_FILEPATH_DOWNLOADS_MAC + fileName);
    }

NOTE: Ive also added a ENUM class that contains the filenames and a method that retrieves the full filename judging by its ENUM name. Wont add it here

================

So the question is:

My test directly just simply checks that I can upload a file (using .sendKeys() method directly on the WebElement) and verify that the label (located below the input field) displays the exact value of the uploaded file (it is developed in such way).

I would like to create a test that actually checks if the FileExplorer is opened upon the click on the "Upload" button on the WebPage.

Thats not something I would mandatory need to do. Thats just out of curiosity. Im interested if it can be done at all.

Thanks

According to the Selenium documentation, "Selenium cannot interact with the file upload dialog". Selenium is designed to interact with the web content loaded in the browser. It has limited support for automating native, operating-system-specific UI components of the browser.

If you really want to verify that the file browser opens, you could try using a tool designed for desktop UI automation specifically. There are several options out there—some open source, some commercial—that can automate file browser dialogs. I tried using desktop automation tools for similar use cases in the past, but never found one that I could wholeheartedly recommend here. If you are curious, maybe have a look at Wikipedia's comparison of GUI testing tools.

My personal recommendation would be not bothering with the file upload dialog at all. Assuming you are creating tests for a web application developed by yourself or your team, it's probably best to focus on testing your application's behavior and avoiding testing browser behavior. Simulating a file upload with Selenium, as you are doing it already, usually is sufficient.