ViewInspector for SwiftUI

ViewInspector is a library for unit testing SwiftUI views. It allows for traversing a view hierarchy at runtime providing direct access to the underlying View structs.

Why?

SwiftUI views are a function of state. We can provide the input, but couldn't verify the output. Until now!

Features

1. Verify the view's inner state

You can dig into the hierarchy and read the actual state values on any SwiftUI View:

func testVStackOfTexts() throws {
    let view = VStack {
        Text("1")
        Text("2")
        Text("3")
    }
    let values = try view.inspect().map { try $0.text().string() }
    XCTAssertEqual(values, ["1", "2", "3"])
}

2. Trigger side effects

You can simulate user interaction by programmatically triggering system-controls callbacks:

let button = try view.inspect().hStack().button(1)
try button.tap()

let list = try view.inspect().list()
try list[5].view(RowItemView.self).callOnAppear()

3. Extract custom views from the hierarchy of any depth

It is possible to obtain a copy of your custom view with actual state and references from the hierarchy of any depth:

let sut = try view.inspect().tabView().navigationView()
    .overlay().anyView().view(CustomView.self).actualView()
XCTAssertTrue(sut.viewModel.isUserLoggedIn)

The library can operate with all types of the View's state: @Binding, @State, @ObservedObject and @EnvironmentObject.

FAQs

Which views and modifiers are supported?

Pretty much all! Check out the detailed list.

The framework is still expanding, as there are hundreds of inspectable attributes in SwiftUI that are not included yet. Contributions are welcomed!

Is it using private APIs?

ViewInspector is using official Swift reflection API to dissect the view structures.

So this framework is production-friendly for the case if you accidentally (or intentionally) linked it with the build target.

How do I add it to my Xcode project?

In Xcode select File ⭢ Swift Packages ⭢ Add Package Dependency...
Copy-paste repository URL: https://github.com/nalexn/ViewInspector
Hit Next two times, under Add to Target select your test target. There is no need to add it to the build target.
Hit Finish

How do I use it in my project?

Please refer to the Inspection guide. You can also check out my other project that harnesses the ViewInspector for testing the entire UI.

kariad/ViewInspector