1. Test Automation For Web-Based Applications
Portnov Computer School
WebDriver Training
Test Automation For Web-Based Applications
Presenter: Ellie Skobel

2. Day 3
Python Modules
and Functions

3. Functions Keyword def introduces a function definition
Function name must start with a letter or _ and it's followed by the parenthesized list of formal parameters.
Body of the function start at the next line, and must be indented.

4. Functions
def function_name(param1, param2): sum = int(param1) + int(param2) if sum % 2: print sum, ' is an even number' return sum
To use the function in your code:
function_name(3, 5)
function_name(2, 3)
sum is an even number
nothing printed

5. This is the correct way:
def function_name(param1, param2): sum = int(param1) + int(param2) if sum % 2 == 0: print sum, ' is an even number' return sum

6. Function's Parameters
Possible to define functions with a variable number of parameters (a.k.a arguments)
Default Argument Values
function can be called with fewer arguments than it is defined to accept
Keyword Arguments
functions can be called using form kwarg=value
Arbitrary Argument Lists
function can be called with an any (infinite) number of arguments

7. Default Argument Values
name argument is required
age argument is optional
False is a default value
def register(name, age=None, married=False): print "Welcome", name.title() if age and int(age) > 20: print "You don't look a day over", int(age)–2 if married: print "Your spouse is very lucky!"
register("John")
register("Jane", 21)
register("Bob", 55, True)
register("Amy", married=True)
register("Ken", age=12, married = False)

8. Keyword Arguments
name argument is required
argument form:
key = value
infinite number of optional arguments
def register(name, **kwargs): print "Welcome", name.title() for key in kwargs.keys(): print key, ":", kwargs[key]
register("John")
register("Jane", age=21)
register("Amy", married=True, gender="female")
register("Jeff", height="6'1", weight=175, children=None)

9. Arbitrary Argument Lists
name argument is required
age argument is optional
infinite number of optional arguments
def register(name, age=18, *args): print "Welcome", name.title() if age < 18: print "You are underage" for num, arg in enumerate(args): print "Argument #{0} is {1}".format(num, arg)
If more that 1 argument given, 2nd one will always be assigned to age
register("John")
register("Jane", 21)
register("Jeff", 21, None)
register("Amy", 20, 30, 40, 50, 60)
register("Steve", None, 42, "Hello")

10. Python function definitions
Modules
A module is a file containing Python definitions and statements
The file name is the module name with the suffix .py appended
Module name is:
common
Python statement
Python function definitions

11. Packages Packages are directories which contain python files (modules)
Packages are a way of structuring modules
The __init__.py files are required to make Python treat the directories as packages
python package named: functions
contains file: __init__.py
regular directory,
NOT a package