Unit testing in SwiftUI

问题

I am trying to write unit tests for SwiftUI views but finding zero resources on the web for how to go about that.

I have a view like the following

struct Page: View {
@EnvironmentObject var service: Service

var body: some View {
    NavigationView {
        ScrollView(.vertical) {
            VStack {
                Text("Some text"))
                    .font(.body)
                    .navigationBarTitle(Text("Title")))

                Spacer(minLength: 100)
            }
        }
   }
}
}

I started writing a test like this

func testPage() {
    let page = Page().environmentObject(Service())
    let body = page.body
    XCTAssertNotNil(body, "Did not find body")
}

But then how do I get the views inside the body? How do I test their properties? Any help is appreciated.

Update: As a matter of fact even this doesn't work. I am getting the following runtime exception

Thread 1: Fatal error: body() should not be called on  ModifiedContent<Page,_EnvironmentKeyWritingModifier<Optional<Service>>>.

回答1:

There is a framework created specifically for the purpose of runtime inspection and unit testing of SwiftUI views: ViewInspector

So the test for your view would look like this:

func testPage() throws {
   let page = try Page().inspect(Service())
   let string = try page.navigationView.scrollView.vStack.text(0).string()
   XCTAssertEqual(string, "Some text")
}