Lecture 5

Lecture 5, Tue 04/16

Pytest, Operator Overloading, Inheritance

Plan for today

join.iclicker.com/YADE
Review
- What is operator overloading? What are the benefits of it?
- What is the difference between the shallow and deep equality?
New for today:
- Why write tests for our code?
- What are the benefits of pytest?
- How to write and run tests in pytest?
- What is inheritance in Python? What are the benefits of it?

Constructors: called to instantiate / create an object of that class
- Default constructor: created by the program by default if the programmer has not specified another constructor
- Instance of a class: a unique creation of an object
Operator overloading: redfining operators:
- ‘def eq(self, rhs): …’ redefines the ‘==’ operator
Shallow vs. deep equality:
- shallow equality: by default, Python uses the memory address (not the value) to determine if two objects are the same
- deep equality: comparing values instead of memory addresses
Test-driven development & Unit testing:
- Testing individual pieces (units) of a program to ensure correct behavior
Pytest: framework that allows us to test our code
- Function names have to begin with “test_”
Inheritance: a way of extending the functionality and properties of an existing class
- Allows us to add new features
- Allows us to replace existing features
- Superclass/parent: class that other classes inherit from
- Subclass/child: class that inherits from a parent class