G2 - unit test

source: AWS

image: AWS

• checks if the block works according to the intended logic

• only interacts with the block via inputs and captures asserts

• it needs to run in isolation with the rest of the program

• test cases are a set of unit tests in a single code block

strategies

• logic check
  • right calculations
  • right path given a correct, expected input
  • all paths covered by the given inputs
• boundary checks
  • system's response to given inputs
  • response to typical inputs, edge cases, invalid inputs
• error handling
  • system's response when errors in inputs

examples

## method
def add_two_numbers(x, y):
    return x + y

## corresponding unit tests
def test_add_positives():
    result = add_two_numbers(5, 40)
    assert result == 45

def test_add_negatives():
    result = add_two_numbers(-4, -50)
    assert result == -54

def test_add_mixed():
    result = add_two_numbers(5, -5)
    assert result == 0  

best practices

• using a unit test framework
  • eg: pytest, unittest
• automate
• assert once
  • a single true/false outcome for each unit test
  • reduces confusion of a failed assert statement in a block of multiple ones

other testing types

• integration testing checks the proper interaction of different parts of the software
• functional testing checks if it passes the system requirement before building
• performance testing checks if it runs to the expected performance requirements (speed, memory size)
• acceptance testing involves manual testing by user groups to see if it performs as required
• security testing checks the software against known vulnerabilities and threats