Lesson 11: Testing

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Testing

def add_double(x, y):
    return 2*(x+y)

def test_add_double():
    expect(add_double(1, 2) == 6)

Why Testing Matters

Structure of a Test

Most test are consist of the same general structure:

Types of Testing

Concept: Mocking

Simulating behavior external to a program so your tests can run independently of other platforms.

You’re testing your program, not somebody else’s. Mock other people’s stuff, not your own.

Testing Frameworks

$ run tests
Finding tests...
Running tests in tests/foo.ext
Running tests in tests/bar.ext
Running tests in misc/test_baz.ext

Frameworks vs ‘The Hard Way’

While you can write tests the hard way:

var = some_function(x)
if var == expected_output:
    continue
else
    print("Test X failed!")

$ run test
Test 5 failed!

It’s usually easier to use a framework.

def simple_test():
    expect(some_function(x), expected_output)

$ run tests
....x.....
Test 5 failed.
Debug information:
...

Teardown and Setup

Useful for:

• populate a test database
• write and delete files
• or anything you want!

def tests_setup():
    connect to database
    populate database with test data

def tests_teardown():
    delete all data from test database
    disconnect from database

def some_test()
    setup is called automaically
    use data in database
    asset something is true
    teardown is run automatically

TODO: Using Python’s unittest

Further Reading

CS 362

This OSU Course covers testing very in depth and even covers types of testing including Random testing and testing analysis.

Python Unittest Documentation

A good reference for using Python’s built-in unit-testing module.