@Test
    @Order(1)
    void advancedMultipleUploadSingleFile(Page page) throws Exception {
        // Arrange
        FileUpload fileUpload = page.fileupload;
        wait4EmptyMesssage(page.uploadedFiles);
        assertEquals("", fileUpload.getValue());

        // Act
        File file = locateClientSideFile("file1.csv");
        fileUpload.setValue(file);
        assertTrue(fileUpload.getWidgetValues().contains(file.getName()), fileUpload.getWidgetValues().toString());
        fileUpload.getAdvancedUploadButton().click();
        wait4File(page.uploadedFiles, file.getName()); // causes sometimes StaleElementReference - why?

        // Assert
        assertNoJavascriptErrors();
        assertUploadedFiles(page.uploadedFiles, file);
        assertConfiguration(fileUpload);
    }
Tests advanced multiple sequential file upload.
p:fileUpload mode=advanced auto=false multiple=true dragDrop=false sequential=true
primefaces-integration-tests/src/test/java/org/primefaces/integrationtests/fileupload/FileUpload009Test.java