Nimble matchers for iOSSnapshotTestCase. Originally derived from Expecta Matchers for FBSnapshotTestCase.

Installing

CocoaPods

You need to be using CocoaPods 0.36 Beta 1 or higher. Your Podfile should look something like the following.

platform :ios, '10.0'

source 'https://github.com/CocoaPods/Specs.git'

# Whichever pods you need for your app go here.

target 'YOUR_APP_NAME_HERE_Tests', :exclusive => true do
  pod 'Nimble-Snapshots'
  pod 'Quick' # if you want to use it with Quick
end

Then run:

$ pod install

Carthage

You need to be using Carthage 0.18 or higher. Your Cartfile (or Cartfile.private) should look something like the following.

github "Quick/Quick" ~> 2.0
github "Quick/Nimble" ~> 8.0
github "uber/ios-snapshot-test-case" "6.0.0"
github "ashfurrow/Nimble-Snapshots"

Then run:

$ carthage bootstrap --platform iOS --toolchain com.apple.dt.toolchain.Swift_3_0

Use

Your tests will look something like the following.

import Quick
import Nimble
import Nimble_Snapshots
import UIKit

class MySpec: QuickSpec {
    override func spec() {
        describe("in some context") {
            it("has valid snapshot") {
                let view = ... // some view you want to test
                expect(view).to( haveValidSnapshot() )
            }
        }
    }
}

There are some options for testing the validity of snapshots. Snapshots can be given a name:

expect(view).to( haveValidSnapshot(named: "some custom name") )

We also have a prettier syntax for custom-named snapshots:

expect(view) == snapshot("some custom name")

To record snapshots, just replace haveValidSnapshot() with recordSnapshot() and haveValidSnapshot(named:) with recordSnapshot(named:). We also have a handy emoji operator.

📷(view)
📷(view, "some custom name")

By default, this pod will put the reference images inside a ReferenceImages directory; we try to put this in a place that makes sense (inside your unit tests directory). If we can't figure it out, or if you want to use your own directory instead, call setNimbleTestFolder() with the name of the directory in your unit test's path that we should use. For example, if the tests are in App/AppTesting/, you can call it with AppTesting.

If you have any questions or run into any trouble, feel free to open an issue on this repo.

Dynamic Type

Testing Dynamic Type manually is boring and no one seems to remember doing it when implementing a view/screen, so you can have snapshot tests according to content size categories.

In order to use Dynamic Type testing, make sure to provide a valid Host Application in your testing target.

Then you can use the haveValidDynamicTypeSnapshot and recordDynamicTypeSnapshot matchers:

// expect(view).to(recordDynamicTypeSnapshot()
expect(view).to(haveValidDynamicTypeSnapshot())

// You can also just test some sizes:
expect(view).to(haveValidDynamicTypeSnapshot(sizes: [UIContentSizeCategoryExtraLarge]))

// If you prefer the == syntax, we got you covered too:
expect(view) == dynamicTypeSnapshot()
expect(view) == dynamicTypeSnapshot(sizes: [UIContentSizeCategoryExtraLarge])

Note that this will post an UIContentSizeCategoryDidChangeNotification, so your views/view controllers need to observe that and update themselves.

For more info on usage, check out the dynamic type tests.

Dynamic Size

Testing the same view with many sizes is easy but error prone. It easy to fix one test on change and forget the others. For this we create a easy way to tests all sizes at same time.

You can use the new haveValidDynamicSizeSnapshot and recordDynamicSizeSnapshot matchers to test multiple sizes at once:

let sizes = ["SmallSize": CGSize(width: 44, height: 44),
"MediumSize": CGSize(width: 88, height: 88),
"LargeSize": CGSize(width: 132, height: 132)]

// expect(view).to(recordDynamicSizeSnapshot(sizes: sizes))
expect(view).to(haveValidDynamicSizeSnapshot(sizes: sizes))

// You can also just test some sizes:
expect(view).to(haveValidDynamicSizeSnapshot(sizes: sizes))

// If you prefer the == syntax, we got you covered too:
expect(view) == snapshot(sizes: sizes)
expect(view) == snapshot(sizes: sizes)

By default, the size will be set on the view using the frame property. To change this behavior you can use the ResizeMode enum:

public enum ResizeMode {
  case frame
  case constrains
  case block(resizeBlock: (UIView, CGSize) -> Void)
  case custom(viewResizer: ViewResizer)
}

To use the enum you can expect(view) == dynamicSizeSnapshot(sizes: sizes, resizeMode: newResizeMode). For custom behavior you can use ResizeMode.block. The block will be call on every resize. Or you can implement the ViewResizer protocol and resize yourself. The custom behavior can be used to record the views too.

For more info on usage, check the dynamic sizes tests.