iOS Unit Testing Like a Boss

Dreamforce '13 #df13 #devzone iOS Unit Testing Like a boss

Transcript

1. iOS Unit Testing Like a Boss Matt Darnall, Salesforce @mdarnall
2. Safe harbor Safe harbor statement under the Private Securities Litigation Reform Act of 1995: This presentation may contain forward-looking statements that involve risks, uncertainties, and assumptions. If any such uncertainties materialize or if any of the assumptions proves incorrect, the results of salesforce.com, inc. could differ materially from the results expressed or implied by the forward-looking statements we make. All statements other than statements of historical fact could be deemed forward-looking, including any projections of product or service availability, subscriber growth, earnings, revenues, or other financial items and any statements regarding strategies or plans of management for future operations, statements of belief, any statements concerning new, planned, or upgraded services or technology developments and customer contracts or use of our services. The risks and uncertainties referred to above include – but are not limited to – risks associated with developing and delivering new functionality for our service, new products and services, our new business model, our past operating losses, possible fluctuations in our operating results and rate of growth, interruptions or delays in our Web hosting, breach of our security measures, the outcome of any litigation, risks associated with completed and any possible mergers and acquisitions, the immature market in which we operate, our relatively limited operating history, our ability to expand, retain, and motivate our employees and manage our growth, new releases of our service and successful customer deployment, our limited history reselling non-salesforce.com products, and utilization and selling to larger enterprise customers. Further information on potential factors that could affect the financial results of salesforce.com, inc. is included in our annual report on Form 10-K for the most recent fiscal year and in our quarterly report on Form 10-Q for the most recent fiscal quarter. These documents and others containing important disclosures are available on the SEC Filings section of the Investor Information section of our Web site. Any unreleased services or features referenced in this or other presentations, press releases or public statements are not currently available and may not be delivered on time or at all. Customers who purchase our services should make the purchase decisions based upon features that are currently available. Salesforce.com, inc. assumes no obligation and does not intend to update these forward-looking statements.
3. Who Is this Guy?
4. Objective-C developers have, for the most part, remained relatively apathetic to Unit Testing ("There's that SenTest thing, but who uses that, really?"). -Mattt Thompson NSHipster.com
5. “.. I don't think we have a problem with tools. We have a cultural problem that we need to fix, and that's something only we (you and me) can do something about. Go and spread the word” -  Luis Solano Nocilla Project
6. Testing doesn’t have to be an afterthought
7. Stand On The Shoulders Of Giants
8. Use tools that support developer efficiency and happiness
9. Learn to write tests you will love
10. The Magic Tricks of Testing Sandi Metz Programmer, Author, Speaker
11. “Good tests aren’t magic, they’re magic tricks. Because they’re tricks you can learn them”
12. You’ll Love Tests that are ü  Thorough ü  Stable ü  Fast ü  Few
13. Focus on messages Object Under Test Incoming Sent To Self Outgoing
14. Message Types Queries: Return something, change nothing Commands: Return nothing, change something
16. Trick #1 Test incoming query messages by making assertions about what they send back
18. Trick #2 Test incoming command messages by making assertions about direct public side effects
20. Trick #3 Don’t test private methods Don’t make assertions about their result Don’t expect to send them
22. Trick #4 Don’t test outgoing query messages Don’t make assertions about their result Don’t expect to send them
24. Trick #5 Expect to send outgoing command messages
26. GitHub Trending Repositories
27. Magic Tricks Applied to iOS
28. UIViewControllers Testing simple things is simple, and testing complex things is complex.
29. Single Responsibility Principle A class should do the smallest possible useful thing; that is, it should have a single responsibility. - Sandi Metz
30. Incoming Query Message make assertions about what is sent back UITableViewDataSource! cellForRowAtIndexPath:! Incoming Queries numberOfRowsInSection:! Demo
31. Incoming Command Message make assertions about direct public side effects ViewController! view! Incoming Command
32. Testing Outlets & Actions 1  Test that outlets exist 2  Test that outlets contain actions back to methods on the controller 3  Send the action command to the controller and assert any public side effects. Demo
33. Outgoing Queries viewWillAppear! ViewController! getTrendingRepositories! GithubSearchClient! Outgoing Query Incoming Query Don’t test outgoing query messages Don’t make assertions about their result Don’t expect to send them Incoming Command
34. Stub the outgoing query message ViewController! getTrendingRepositories! Test Double! Stubs provide “canned” answers to calls made during the test Outgoing Query
35. Dependency Injection ViewController! Pass dependencies via an initializer (aka Constructor Injection) initWithSearchClient! Demo
36. Outgoing Commands Model! postNotification! NotificationCenter! Expect to send outgoing command messages Outgoing Command
37. Controller! addObserver! Outgoing Command Outgoing Commands Expect to send outgoing command messages NotificationCenter!
38. Mock the Outgoing Command Message Object Under Test! message! Test Double! Mocks are test doubles that record calls and can be verified Outgoing Command Demo
39. Magic Tricks Applied to iOS
40. Thanks! ü  More Resources: http://bit.ly/HvRbZQ ü  Sandi Metz @sandimetz ü  Contact me: @mdarnall ü  Get involved and spread the word!
41. Matt Darnall @mdarnall mdarnall.com