CODEWITHSUNDEEP
pythonfunctionclasstestingpython-3.3
user300
user300

Reputation: 465

How to test my code

I'm having trouble getting the output I want for my code. I want to test a class and the functions defined in the class. This is my code:

class Book:
    # the class constructor
    def __init__(self, author, title, book_id):
        self.title = title
        self.author = author
        self.book_id = book_id      
    def __str__(self):
        s = "Books("+self.author+", "+self.title+", "+self.book_id+")"
        return s
    def __repr__(self):
        return str(self)

What I did to try to attempt to test it is this:

 >>> author="Dr. Suess"
>>> title="The Cat in the Hat"
>>> book_id="12345"
>>> Book
<class '__main__.Book'>
>>>

the output I get is the last line. I'm probably doing it wrong but I don't know how to test it. If someone can show me that would be great!

Upvotes: 2

Views: 180

Answers (2)

Matthew
Matthew

Reputation: 2300

When you type Book into the interpreter, you're getting the actual Book class' representation as output. __repr__ and __str__ both refer to the instance of a Book, not to the class itself. So to test this, you have to instantiate a Book:

>>> b = Book("Dr. Suess", "The Cat in the Hat", "12345")
>>> b
"Books(Dr. Suess, The Cat in the Hat, 12345)"

Remember - a class is like a blueprint for an instance. In this case, Book defines what it means to be a Book, but it doesn't actually define an actual Book object - to do that, you need to make a Book instance using the code I did.

Upvotes: 2

Nafiul Islam
Nafiul Islam

Reputation: 82470

>>> Book
<class '__main__.Book'>

When one does the above in the console, it does not call the __repr__ method created on instance. Let me explain, Book is merely a class object, its not an instance, because you have not called any arguments to it, however, if you do call arguments, this is what you get:

>>> from Books import Book
>>> Book
<class Books.Book at 0x027B0AE8>
>>> Book("Hello", "World", '1234')
Books(Hello, World, 1234)

As you can see, because we created an instance of a method, we were able to get the __repr__ to be called.

Upvotes: 0

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