Hi everyone, I'm new to writing test classes and need help to create one of the test class.
Below is the class that I created. can someone help me with the test class for it?

public with sharing class customFileUploadctrl {
    @AuraEnabled(cacheable=true)
    public static List<file> getRelatedFiles(String recordId){
        List<File> files = new List<File>();

        for(ContentDocumentLink conLink : [SELECT 
                                                ContentDocument.Id, 
                                                ContentDocument.Title, 
                                                ContentDocument.CreatedDate, 
                                                ContentDocument.FileType,
                                                ContentDocument.Description
                                                    FROM ContentDocumentLink 
                                                        WHERE LinkedEntityId =: recordId]){
            File file = new File();
            file.Title = conLink.ContentDocument.Title;
            file.Id = conLink.ContentDocument.Id;
            file.CreatedDate = conLink.ContentDocument.CreatedDate;
            file.Type = conLink.ContentDocument.FileType;
            file.Description = conLink.ContentDocument.Description;
            files.add(file);
        }
        return files;
    }


    public class File{
        @AuraEnabled public String Title;
        @AuraEnabled public String Type;
        @AuraEnabled public Id Id;
        @AuraEnabled public Datetime CreatedDate;
        @AuraEnabled public String Description;
    }
}