Add a snapshot test

Tests/GravatarUITests/CropFrameOverlayViewTests.swift

@@ -0,0 +1,39 @@
+@testable import GravatarUI
+import SnapshotTesting
+import XCTest
+
+final class CropFrameOverlayViewTests: XCTestCase {
+    enum Constants {
+        static let imageSize: CGSize = .init(width: 320, height: 480)
+    }
+
+    override func invokeTest() {
+        withSnapshotTesting(record: .failed) {
+            super.invokeTest()
+        }
+    }
+
+    @MainActor
+    func testCropFrameOverlay() throws {
+        let image = UIImage.create(size: Constants.imageSize)
+        let imageView = UIImageView(image: image)
+        imageView.translatesAutoresizingMaskIntoConstraints = false
+        imageView.widthAnchor.constraint(equalToConstant: Constants.imageSize.width).isActive = true
+        imageView.heightAnchor.constraint(equalToConstant: Constants.imageSize.height).isActive = true
+        imageView.contentMode = .scaleAspectFill
+        let containerView = CropFrameOverlayView()
+        // center the cropping layer
+        containerView.scrollViewFrame = .init(
+            origin: .init(x: 0, y: (Constants.imageSize.height - Constants.imageSize.width) / 2),
+            size: .init(width: Constants.imageSize.width, height: Constants.imageSize.width)
+        )
+        containerView.translatesAutoresizingMaskIntoConstraints = false
+        containerView.widthAnchor.constraint(equalToConstant: Constants.imageSize.width).isActive = true
+        containerView.heightAnchor.constraint(equalToConstant: Constants.imageSize.height).isActive = true
+        imageView.addSubview(containerView)
+        containerView.centerXAnchor.constraint(equalTo: imageView.centerXAnchor).isActive = true
+        containerView.centerYAnchor.constraint(equalTo: imageView.centerYAnchor).isActive = true
+        containerView.backgroundColor = .clear
+        assertSnapshot(of: imageView, as: .image)
+    }
+}

Tests/GravatarUITests/UIImageAdditionsTests.swift

@@ -4,7 +4,7 @@ import XCTest
 final class UIImageAdditionsTests: XCTestCase {
     @MainActor
     func testSquareUnequalEdgesSmallerThanMax() throws {
-        let image = try XCTUnwrap(createImage(size: .init(width: 96.1, height: 96.0)))
+        let image = try XCTUnwrap(UIImage.create(size: .init(width: 96.1, height: 96.0)))
         let squareImage = try XCTUnwrap(image.square(maxLength: 1024))
         let targetLength = min(image.size.width * image.scale, image.size.height * image.scale)
         XCTAssertEqual(squareImage.size.width, squareImage.size.height)
@@ -15,7 +15,7 @@ final class UIImageAdditionsTests: XCTestCase {
     @MainActor
     func testSquareUnequalEdgesBiggerThanMax() throws {
         let maxLength: CGFloat = 50.0
-        let image = try XCTUnwrap(createImage(size: .init(width: 96.1, height: 96.0)))
+        let image = try XCTUnwrap(UIImage.create(size: .init(width: 96.1, height: 96.0)))
         let squareImage = try XCTUnwrap(image.square(maxLength: maxLength))
         XCTAssertEqual(squareImage.size.width, squareImage.size.height)
         XCTAssertEqual(squareImage.size.width * squareImage.scale, maxLength)
@@ -25,7 +25,7 @@ final class UIImageAdditionsTests: XCTestCase {
     @MainActor
     func testSquareEqualEdgesBiggerThanMax() throws {
         let maxLength: CGFloat = 50.0
-        let image = try XCTUnwrap(createImage(size: .init(width: 96.0, height: 96.0)))
+        let image = try XCTUnwrap(UIImage.create(size: .init(width: 96.0, height: 96.0)))
         let squareImage = try XCTUnwrap(image.square(maxLength: maxLength))
         XCTAssertEqual(squareImage.size.width, squareImage.size.height)
         XCTAssertEqual(squareImage.size.width * squareImage.scale, maxLength)
@@ -34,15 +34,17 @@ final class UIImageAdditionsTests: XCTestCase {
 
     @MainActor
     func testSquareEqualEdgesSmallerThanMax() throws {
-        let image = try XCTUnwrap(createImage(size: .init(width: 96.1, height: 96.1)))
+        let image = try XCTUnwrap(UIImage.create(size: .init(width: 96.1, height: 96.1)))
         let squareImage = try XCTUnwrap(image.square(maxLength: 1024))
         let targetLength = min(image.size.width * image.scale, image.size.height * image.scale)
         XCTAssertEqual(squareImage.size.width, squareImage.size.height)
         XCTAssertEqual(squareImage.size.width * squareImage.scale, targetLength)
         XCTAssertEqual(squareImage.size.height * squareImage.scale, targetLength)
     }
+}
 
-    private func createImage(color: UIColor = .blue, size: CGSize) -> UIImage? {
+extension UIImage {
+    static func create(color: UIColor = .blue, size: CGSize) -> UIImage? {
         UIGraphicsBeginImageContextWithOptions(size, false, 0)
         color.setFill()
         UIRectFill(CGRectMake(0, 0, size.width, size.height))