#+LaTeX_CLASS: beamer
#+LaTeX_CLASS_OPTIONS: [presentation]
#+BEAMER_FRAME_LEVEL: 1

#+BEAMER_HEADER_EXTRA: \usetheme{Warsaw}\usecolortheme{default}\useoutertheme{infolines}\setbeamercovered{transparent}
#+COLUMNS: %45ITEM %10BEAMER_env(Env) %10BEAMER_envargs(Env Args) %4BEAMER_col(Col) %8BEAMER_extra(Extra)
#+PROPERTY: BEAMER_col_ALL 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 :ETC

#+LaTeX_CLASS: beamer
#+LaTeX_CLASS_OPTIONS: [presentation]

#+LaTeX_HEADER: \usepackage[english]{babel} \usepackage{ae,aecompl}
#+LaTeX_HEADER: \usepackage{mathpazo,courier,euler} \usepackage[scaled=.95]{helvet}

#+LaTeX_HEADER: \usepackage{listings}

#+LaTeX_HEADER:\lstset{language=Python, basicstyle=\ttfamily\bfseries,
#+LaTeX_HEADER:  commentstyle=\color{red}\itshape, stringstyle=\color{red},
#+LaTeX_HEADER:  showstringspaces=false, keywordstyle=\color{blue}\bfseries}

#+TITLE:     Testing and debugging
#+AUTHOR:    FOSSEE
#+EMAIL:     
#+DATE:    

#+DESCRIPTION: 
#+KEYWORDS: 
#+LANGUAGE:  en
#+OPTIONS:   H:3 num:nil toc:nil \n:nil @:t ::t |:t ^:t -:t f:t *:t <:t
#+OPTIONS:   TeX:t LaTeX:nil skip:nil d:nil todo:nil pri:nil tags:not-in-toc

* Outline 
  - What software Testing is? 
  - Learn to test simple functions for their functionality.
  - Learn how to automate tests. 
  -  Need for coding style and some of the standards followed by the Python Community.
  -  Handling Errors and Exceptions.

* gcd function
  - Create gcd.py file with:
#+begin_src python
  def gcd(a, b):
        if a % b == 0: 
            return b
        return gcd(b, a%b)
#+end_src python

* Test for gcd.py
  - Edit gcd.py file
#+begin_src python 
  def gcd(a, b):
      if b == 0:
          return a
      return gcd(b, a%b)
  
  if __name__=='__main__':
      result = gcd(48, 64)
      if result != 16:
          print "Test failed"
      print "Test Passed"

#+end_src

* Automating tests
#+begin_src python
    if __name=__='__main__':
    for line in open('numbers.txt'):
        numbers = line.split()
        x = int(numbers[0])
        y = int(numbers[1])
        result = int(numbers[2])
        if gcd(x, y) != result:
            print "Failed gcd test
                          for", x, y
#+end_src

* Question 1
  For the same inputs as gcd write automated tests for LCM.
* Solution 1
#+begin_src python
  def gcd(a, b):
        if a % b == 0: 
            return b
        return gcd(b, a%b)

   def lcm(a, b):
        return (a * b) / gcd(a, b)

    if __name__ == '__main__':
      for line in open('lcmtestcases.txt'):
        numbers = line.split()
        x = int(numbers[0])
        y = int(numbers[1])
        result = int(numbers[2])
       	if lcm(x, y) != result:
            print "Failed lcm test for", x, y

#+end_src

* Meaning full names
#+begin_src python   
   
   amount = 12.68
   denom = 0.05
   nCoins = round(amount / denom)
   rAmount = nCoins * denom

#+end_src

* Code style
 - Four Space Indentation
 - 79 character limit on a line
 - Funtions should be seperated by 
   blank line
 - Use Docstring
 - White space around operators 
   - l = 32 % 4

* Question 2
   - Give meaningful names to the variables in following
     code
	
     - c = a / b

* Solution 2
#+begin_src python

  quotient = dividend / divisor

#+end_src

* Code Snippet
#+begin_src python
   
  while True print 'Hello world'

#+end_src

* Error
#+begin_latex
\begin{lstlisting}
 while True print 'Hello world'
 \end{lstlisting}
  \begin{lstlisting}
  File "<stdin>", line 1, in ?
    while True print 'Hello world'
SyntaxError: invalid syntax
\end{lstlisting}
#+end_latex

* Code Snippet
#+begin_src python
  a = raw_input("Enter a number")
  try:
	num = int(a)
   except:
	print "Wrong input ..."

#+end_src

* Using idb
#+begin_latex
\small
\begin{lstlisting}
In []: import mymodule
In []: mymodule.test()
---------------------------------------------
NameError   Traceback (most recent call last)
<ipython console> in <module>()
mymodule.py in test()
      1 def test():
      2     total=1+1
----> 3     print spam
NameError: global name 'spam' is not defined

In []: %debug
> mymodule.py(2)test()
      0     print spam
ipdb> total
2
\end{lstlisting}

#+end_latex



* Summary
 - Create simple tests for a function.
 - Learn to Automate tests using many predefined test cases.
 - Good coding standards.
 - Difference between syntax error and exception.
 - Handling exception using try and except.
 - Using %debug for debugging on ipython.

* Thank you!
#+begin_latex
  \begin{block}{}
  \begin{center}
  This spoken tutorial has been produced by the
  \textcolor{blue}{FOSSEE} team, which is funded by the 
  \end{center}
  \begin{center}
    \textcolor{blue}{National Mission on Education through \\
      Information \& Communication Technology \\ 
      MHRD, Govt. of India}.
  \end{center}  
  \end{block}
#+end_latex