def calculate_test_values(
    total_words, ocr_recognized_words, 
    tp, tn, fn
    ): 
    """
    Calculates the model test values :
    TP : True Positive  (There are words and every word has been recognized)
    TN : True Negative  (There is no word and no word has been recognized)
    FP : False Positive (There is no word but a word (or more) has been recognized)
    FN : False Negative (There are words and NOT every word has been recognized)
    """
    
    if total_words == 0:
        tn += 1
    else:
        if ocr_recognized_words/total_words == 1:
            tp += 1
        else:
            fn += 1
    return (tp, tn, fn)