Question

I have a method that writes to a file with a given name. Do I have to test this method and, if so, for what should I test it?

public void record(Object o){
    try{

        FileWriter fileStream = new FileWriter("data.txt", true);
        BufferedWriter out = new BufferedWriter(fileStream);

        out.write(o.toString());
        out.newLine();  
        out.close();

    } catch (Exception e){
        System.err.println("Error: " + e.getMessage());
    }
}

Answer 1

Whether you have to test is or not is a question for your project lead. If it’s determined you should write some tests, then I would test at least these cases

• Happy path (write a good object, check the file contents afterwards)
• What happens with a null argument (file exist? what’s in it? Does it get closed?)
• What happens if the method is called multiple times?
• What happens if the file already exists, but is not writeable