AUTOMATED TESTING ON IOS

AGENDAFundamentals of automated tests

Different Types of Tests

Unit Tests

Integration Tests

UI Tests

Demo

FUNDAMENTALS OF AUTOMATED TESTS

FUNDAMENTALS

Write code to specify & verify behavior of application

When I attempt to log inAnd the provided password is incorrectI expect to see an error message

What is being tested?

How is it being tested?

What is the expected result?

FUNDAMENTALSWithout tests you:

1. Change code

2. Restart App

3. Set up required state & navigate to part of app you are testing

4. Find out the behavior is still wrong, start over at 1.

⌘+R → 🕐🕑🕒

FUNDAMENTALS

An application with good test coverage can be validated

almost entirely in a few seconds

⌘+U → ✅

You can even run this on a CI Server!

CONTINOUS INTEGRATION SERVERS

JenkinsTravis-CI Circle-CI

Run automated tests upon every push to repository - send notifications to you and team members when tests break!

SUMMARY

When I attempt to log inAnd the provided password is incorrectI expect to see an error message

Tests describe your application’s behavior to other developers and product owners! They allow you to automatically verify correctness of application!

DIFFERENT TYPES OF TESTS

DIFFERENT TYPES OF TESTS

Unit Tests - Verify the behavior of one individual unit of work

Integration Tests - Test entire features, e.g. login while connecting to a

backend server

UI Tests - Interact with your application through the regular UI elements,

specific form of integration test

Which code is broken?

Which feature is broken?

Can the user interact with UI as expected?

UNIT TESTS

FEATURES OF A UNIT TEST

Runs isolated from any other test, sets up its entire environment

Only tests a single unit of code - all this code’s dependencies need to be mocked out (details later)

HOW TO WRITE A UNIT TEST

Arrange set up the state that the test needs to run - e.g. create

the object you want to test

Act interact with your code - e.g. call a method on the created

object

Assert verify the result - e.g. check that the state of the object

changed as expected

HOW TO VERIFY UNIT TESTS

Return Value you call a function/method and assert on the

return value

State Change you call a method and assert that the state of

the object changed

Interaction you call a method and make sure that the object

calls another object

HOW TO ISOLATE UNIT TESTS

Stubs return predefined results for method calls/properties

Mocks are used to verify that a method has been called on a

given object

Fakes behave similar to the real object but take shortcuts in implementation (complex Stubs)

INTEGRATION TESTS

FEATURES OF AN INTEGRATION TEST

Less strict than a Unit Test, can test a larger portion of functionality

Is allowed to depend on outside resources, e.g. a database or a web service

Useful for testing a feature in its real environment

Higher chance of “false positives”

UI TESTING

FEATURES OF AN UI TEST

Specific form of integration test that tests your app entirely

through the UI

Xcode 7 provides support for recording UI tests

SUMMARY

SUMMARY

There are two broad categories of automated tests, Unit Tests

and Integration Tests

Automated tests allow us to verify applications fast and reliably

Automated tests inform us about breaking changes to existing

features

ADDITIONAL RESOURCES

ADDITIONAL RESOURCES

Book by Roy Osherove: The Art of Unit Testing

Blog Post: iOS Testing in 2015

iOS Unit Testing Blog

Blog Post: Mocking in Swift

LIVE CODING: NUMBER GUESSING GAME

NUMBER GUESSING GAME1. Computer guesses a number within a specified range

2. You attempt to guess number

3. Computer tells you whether you were correct or whether

number was too low or too high

4. You repeat step 2.-4. until you guessed the number

successfully