Week 2: Unit Testing, More OOP and Composition

Learning objectives:

  • Describe and apply the principles of Unit testing and Test Driven Development
  • Use objects as input and output for functions
  • Recognize how and when to appropriate use const and static class members
  • Use composition to build objects from other objects

Deadlines This Week:

  • Monday 11:59PM - Assignment 1.
  • Fri 11:59PM - CppLab Object Oriented Thinking
  • Saturday 11:59PM - CppLab Composition

Classroom Recaps:

Monday
  • Introduction to Unit Testing
  • Work through UnitTesting Guide Make sure to pull an updated copy of the CS162 source code before starting.
Tuesday
  • Read 10.3-10.4
  • Objects, Functions, & Arrays
  • Read 10.5-10.6, 10.10
  • Static, Const, Interacting Objects - note the book does not have great examples of interacting objects... review class power points/examples for those.
  • CPPLab - OOThinking
Wednesday
  • Read 10.8 and - learncpp.com Ch 10.1/10.2 for Composition
  • Read 10.7, 10.11 - OODesign
  • CPPLab - Composition
Friday
  • Pointer review
  • Read 11.2-4, 11.6, 11.7
  • Git Tutorial - follow the instructions in parts 2/3 to make your own cs162 repository and add some files to it.

Online Activity Outline:

Unit Tests & Test Driven Development

  • Watch this videos:
    Unit Testing Concepts
     Unit Testing Details
  • Work through the UnitTesting Guide - you can find the starter code in Github (UnitTestDemo).
    You will have to write unit tests for your code this week, so make sure to practice getting things set up. You can peek at my UnitTestDemoCompleted folder in the Github repository for examples of written unit tests.
  • These optional readings explain test driven development:

Object Passing & Objects with Arrays

  • Read 10.3-10.4
  • Grab an updated copy of the CS162 Github repository and try out the code in the ObjectFunctionsArrays project. This video explains it:
    Objects with Functions & Arrays

Static, Const and Interacting Objects

  • Read 10.5-10.6, 10.10 - Static, Const, Interacting Objects.
  • The book does not have good examples of interacting objects... review video, sample code for those (Circle functions that take a Point).
    Const Members & Interaction
     Static Members
  • Do CPPLab - OOThinking

OOD and Composition

  • Read 10.7 and 10.11 for general advice about designing objects - I have one extra point to add:
    Single Representation: We only want to represent each piece of information once. If you already have a piece of data represented in a class, or the information to calculate it, you should not store it again. For example, in the Circle class, we might have a getArea() function, but do not have an area variable. getArea() can calculate the area whenever it is needed by using the radius which we already store. If we stored area explicitly, it would be much easier to do something dumb like change the radius of the circle and forget to update the area. Only if after testing do we realize the calculation takes an inordinate amount of time (say we need to get a circle's area thousands of times per second) should we worry about explicitly storing the calculated value it.
  • Read 10.8 about Composition. I think the treatment there is a bit weak, so I also HIGHLY recommend reading learncpp.com Ch 10.1/10.2 about Composition.
  • This video walks through a sample of using composition
    Object Composition

Pointers Review

This material really goes with next week... you do not need it for this week's assignment.
  • Learning to think in terms of pointers is one of the biggest abstractions you will have to learn in CS. Go back to week 10 of CS161 and watch the pointer basics video. Reread 11.1 and 11.2.
  • Read 11.3-11.4, 11.6. This material expands on the basics from 161.
  • Watch this video (related code is in the Github repository)
    Pointers & Functions
  • Do the Pointer Worksheet from the Classroom files link - it is similar to the one from CS161 but has more problems. Start by reading the PointerWSExample file - it shows you how you should record the effects of lines of code. Use the PointerWSKey to check your work.

Git Setup

In week 01 we introduced source control so that you could access my code. Now is a good time for you to set up your own repository for your code. Doing so (and using it) means you will be able to always access your code wherever you are.

  • Git Tutorial - follow the instructions in parts 2/3 to make your own cs162 repository and add some files to it.

Extra Info:

Learncpp.com

This online tutorial covers some of the same ground as the Liang readings:
LearnCpp.com chapters 8.10-8.11, 10.1-10.2

Assignment:

Assignment #2 - Note that the setup is a bit complex, but there are instructions for how to get things rolling. There is a sample in the Github repository (Assign2CircleSample) that shows my Circle composition project set up with a separate test project like yours should be.

Classroom slides/examples:

Directory of classroom files from the week
Right click files and save to your computer