Book Image

Django 1.1 Testing and Debugging

Book Image

Django 1.1 Testing and Debugging

Overview of this book

Bugs are a time consuming burden during software development. Django's built-in test framework and debugging support help lessen this burden. This book will teach you quick and efficient techniques for using Django and Python tools to eradicate bugs and ensure your Django application works correctly. This book will walk you step by step through development of a complete sample Django application. You will learn how best to test and debug models, views, URL configuration, templates, and template tags. This book will help you integrate with and make use of the rich external environment of test and debugging tools for Python and Django applications. The book starts with a basic overview of testing. It will highlight areas to look out for while testing. You will learn about different kinds of tests available, and the pros and cons of each, and also details of test extensions provided by Django that simplify the task of testing Django applications. You will see an illustration of how external tools that provide even more sophisticated testing features can be integrated into Django's framework. On the debugging front, the book illustrates how to interpret the extensive debugging information provided by Django's debug error pages, and how to utilize logging and other external tools to learn what code is doing.
Table of Contents (17 chapters)
Django 1.1 Testing and Debugging
Credits
About the Author
About the Reviewer
Preface
Index

Understanding and fixing the TypeError


What went wrong that led to the debug page we've encountered here? In this case, the basic error information is enough to identify and fix the problem. We have a TypeError reported, with an exception value of __init__() takes at least 2 non-keyword arguments (1 given). Furthermore, the location of the code that caused the error is /dj_projects/marketr/survey/forms.py in QuestionVoteForm, line 3. Looking at that line we see:

    answer = forms.ModelChoiceField(widget=forms.RadioSelect) 

We have not specified all of the necessary arguments to create a ModelChoiceField. If you are new to Python, the specifics of the error message may be a bit confusing, as that line of code doesn't reference anything named __init__ nor does it appear to pass any non-keyword arguments, yet the message says one was given. The explanation for that is that __init__ is the method called by Python when an object is created, and it, like all object instance methods, automatically...