AnimatedImage Unit Testing with UIViewRepresentable and ViewInspector

AnimatedImageTests.swift

extension AnimatedImage {
    struct WrapperView: View & Inspectable {
        var name: String
        var bundle: Bundle?
        @State var isAnimating: Bool

        var onViewUpdate: (Self, PlatformView, AnimatedImage.Context) -> Void

        var body: some View {
            AnimatedImage(name: name, bundle: bundle, isAnimating: $isAnimating)
            .onViewUpdate { view, context in
                self.onViewUpdate(self, view, context)
            }
        }
    }
}

func testAnimatedImageBinding() throws {
    let expectation = self.expectation(description: "AnimatedImage binding control")
    var viewUpdateCount = 0
    // Use wrapper to make the @Binding works
    let wrapperView = AnimatedImage.WrapperView(name: "TestLoopCount.gif", bundle: TestUtils.testImageBundle(), isAnimating: true) { wrapperView, view, context in
        viewUpdateCount += 1
        guard let animatedImageView = view as? SDAnimatedImageView else {
            XCTFail("AnimatedImage's view should be SDAnimatedImageView")
            return
        }
        if let animatedImage = animatedImageView.image as? SDAnimatedImage {
            XCTAssertEqual(animatedImage.animatedImageLoopCount, 1)
            XCTAssertEqual(animatedImage.animatedImageFrameCount, 2)
        } else {
            XCTFail("AnimatedImage's image should be SDAnimatedImage")
        }
        switch viewUpdateCount {
        case 1:
            // #1 SwiftUI's first-time updateUIView call
            #if os(iOS) || os(tvOS)
            XCTAssertTrue(animatedImageView.isAnimating)
            #else
            XCTAssertTrue(animatedImageView.animates)
            #endif
        case 2:
            // #2 AnimatedImage's imageModel @ObservedObject trigger update
            #if os(iOS) || os(tvOS)
            XCTAssertTrue(animatedImageView.isAnimating)
            #else
            XCTAssertTrue(animatedImageView.animates)
            #endif
            DispatchQueue.main.async {
                wrapperView.isAnimating = false
            }
        case 3:
            // #3 AnimatedImage's isAnimating @Binding trigger update (from #2)
            #if os(iOS) || os(tvOS)
            XCTAssertFalse(animatedImageView.isAnimating)
            #else
            XCTAssertFalse(animatedImageView.animates)
            #endif
            expectation.fulfill()
        default:
            // Should only update 3 times
            XCTFail()
        }
    }
    ViewHosting.host(view: wrapperView)
    self.waitForExpectations(timeout: 5, handler: nil)
}