Why Is Random Test Order a Big Deal for Test Quality?
Have you ever seen a unit test pass in isolation, but fail when run in a suite? Or vice versa, pass in a suite, but fail when run in isolation?
Besides the other improvements for test-centric workflows, Xcode 10 brings a rarity: a new XCTest feature for unit tests! Randomizing test order will help us flush out mistakes in the design of our tests.
Let’s start by examining a symptom… Have you ever seen naming like this in a test suite?
func test01RunThisTestFirst() { … }
func testCheckSomethingElse() { … } Joy! Xcode 10 Promises to Improve Test-Centric Workflows
Every WWDC, I hope for improvements to unit testing — but have learned to expect disappointment. So at WWDC 2018, I was surprised to have my low expectations thwarted! Xcode 10 brings changes that will improve my test-centric workflow.
For several years, Apple’s changes for test support have underwhelmed me. They focused on:
- Xcode Bots (…I tried them. I gave up.)
- Performance tests (…My code is not performance-critical.)
- UI tests (…I don’t write any.)
With Test Driven Development, unit tests run locally are my primary tool. The features above may have helped some people, but I wasn’t one of them.
So what did WWDC 2018 bring me? Here’s what I see on the horizon with Xcode 10.Continue reading
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Do You Refactor without Tests? It’s Time for Safety
When you refactor, do you have unit tests covering you? …If not, why not? …If so, how do you know?
Source: http://www.ntd.tv/2017/02/14/2016-fails-will-stay-ever/
To me, it seems that the state of refactoring has gotten worse across the industry. Both managers and programmers and managers say the word “refactoring” more than ever. But they almost always mean, “I’m going to change a bunch of stuff. Then at the end, we need to make sure I didn’t break anything.”
But that’s not refactoring. That’s rewriting.
How to Improve Code Comments with Little Refactorings
Does your code have comments? Sometimes they’re helpful. But most of the time…
Don’t litter by Valerie Everett, used under CC BY-SA 2.0
Code Smells: How Many Do You See in This Method?
It’s time for a quick exercise in code smells!
Striped Skunk (Mephitis mephitis) DSC_0030 by Dan Dzurisin, used under CC BY 2.0
How many code smells do you see below?
The 3 Laws of TDD: Focus on One Thing at a Time
When I was first learning TDD, I’d try to get to the First Step (a failing test) by writing a fully-formed test. But it often took a lot fiddling to get that test to run and fail. Sometimes this was because the production code took several steps to set up. Sometimes it was because the test code wasn’t right.
One of the tricky parts of TDD is that we’re creating two streams of code in parallel: the test code, and the production code. Two things changing at the same time… that’s a hard thing to keep in your head!
My Crazy Plans for the New Year (Book Teaser)
Happy new year! It seems like good time for a Quality Coding retrospective. I also want to share some goals for 2018.
…Did someone say, “Are you writing a book?”
How to Mock Standalone Functions …Without Changing the Call Sites
We’ve looked at ways to mock methods in Swift. But what about standalone functions? Is there a way to mock them as well?
Yes! Not only can we mock Swift standalone functions, but we can do it without changing the call sites.
The last stand by Carl Jones, used under CC BY-NC 2.0
How to Use SwiftLint for Clean, Idiomatic Swift
We get feedback from the compiler. We get feedback from Test Driven Development. But what sources of feedback lie in between?
This is where linters come in. A linter goes beyond “Does the code compile?” A linter answers questions like, “Is the code idiomatic? Is it stylistically clean? Are there any red flags?”
MAGNIFYING GLASS by Rafael Anderson Gonzales Mendoza, used under CC BY-NC-SA 2.0
What Can We Learn from an Incorrect TDD Diagram?
A paper published in 2013 about Test Driven Development included the following diagram. Unfortunately, it gets some things wrong:
