FBSnapshotTestCase

Presented @ Swift Meetup Hamburg

Sample code: https://github.com/pietbrauer/Beverages

Transcript

1. FBSnapshotTestCase @pietbrauer
2. Who developed an app before?
3. Who wrote tests for it?
4. Why didn't you?
5. You wanted to get your killer App idea on Kickstarter ASAP
6. Winners don’t test
7. Most is view code is hard to test
8. What do I mean with that?
9. Our app
10. We have ... • a simple UITableViewController setup • a Beverage model • a BeverageCell cell that displays data
11. We want to ... • test cell interactions • setting texts on labels • interacting with the stepper • view layout code
12. Model tests func testBeer() { let subject = Beverage.Beer XCTAssertEqual(subject.amount, 0.5) XCTAssertEqual(subject.description, "Beer (0.5 l)") XCTAssertEqual(subject.emoji, "!") }
13. Model logic tests func testSettingAmountDrunk() { var subject = Beverage.Tea // reset units drunk subject.unitsDrunk = 0 XCTAssertEqual(subject.unitsDrunk, 0) // set new value subject.unitsDrunk = 5 XCTAssertEqual(subject.unitsDrunk, 5) // Take other instance of tea and check if same amount applies let secondSubject = Beverage.Tea XCTAssertEqual(subject.unitsDrunk, 5) }
14. Cell View tests func testCellConfiguration() { var beverage = Beverage.Beer beverage.unitsDrunk = 3 let subject = BeverageCell(style: .Default, reuseIdentifier: nil) subject.configure(beverage) XCTAssertEqual(subject.beverageEmojiLabel.text!, "!") XCTAssertEqual(subject.beverageNameLabel.text!, "Beer (0.5 l)") XCTAssertEqual(subject.amountDrunkLabel.text!, "3 drunk today") XCTAssertEqual(subject.stepper.value, 3) }
15. Cell Logic tests func testStepper() { var beverage = Beverage.Beers beverage.unitsDrunk = 0 let subject = BeverageCell(style: .Default, reuseIdentifier: nil) subject.configure(beverage) // Set stepper value subject.stepper.value = 5 subject.stepperStepped(subject.stepper) // Expect that the amount drunk label has the right value XCTAssertEqual(subject.amountDrunkLabel.text!, "5 drunk today") }
18. Actual app
19. What to do? Write snapshot tests
20. Installation # Cartfile github "facebook/ios-snapshot-test-case" >= 2.0 # Podfile pod "FBSnapshotTestCase", ">= 2.0"
21. Usage 1. import FBSnapshotTestCase 2. Inherit from FBSnapshotTestCase 3. In setUp() set recordMode = true 4. Run unit tests 5. Remove setUp()
22. Demo
24. Links • FBSnapshotTestCase: https://github.com/facebook/ios- snapshot-test-case • Demo project: https://github.com/pietbrauer/Beverages • Snapshots Xcode plugin: https://github.com/orta/snapshots
25. Thanks Twitter: @pietbrauer Blog: nerdishbynature.com/blog