Add a sample snapshot test for a SwiftUI View

Tests/GravatarUITests/AvatarPickerProfileViewTests.swift

@@ -0,0 +1,37 @@
+@testable import GravatarUI
+import SnapshotTesting
+import SwiftUI
+import XCTest
+
+final class AvatarPickerProfileViewTests: XCTestCase {
+    override func invokeTest() {
+        withSnapshotTesting(record: .failed) {
+            super.invokeTest()
+        }
+    }
+
+    @MainActor
+    func testAvatarPickerProfileView() throws {
+        let testView = AvatarPickerProfileView(
+            avatarURL: .constant(nil),
+            model: .constant(
+                .init(
+                    displayName: "Shelly Kimbrough",
+                    location: "San Antonio, TX",
+                    profileURL: URL(string: "https://gravatar.com")
+                )
+            ),
+            isLoading: .constant(false)
+        )
+        // put a border around so the bounds can be visible in the snapshots.
+        .markBounds()
+
+        assertSnapshots(
+            of: testView,
+            as: [
+                .testStrategy(userInterfaceStyle: .light),
+                .testStrategy(userInterfaceStyle: .dark),
+            ]
+        )
+    }
+}

Tests/GravatarUITests/Snapshotting+Additions.swift

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+import SnapshotTesting
+import SwiftUI
+import XCTest
+
+extension Snapshotting where Value: SwiftUI.View, Format == UIImage {
+    static func testStrategy(userInterfaceStyle: UIUserInterfaceStyle = .light) -> Self {
+        let deviceConfig: ViewImageConfig = .iPhone13
+        let traits = UITraitCollection(traitsFrom: [
+            UITraitCollection(displayScale: deviceConfig.traits.displayScale),
+            UITraitCollection(userInterfaceStyle: userInterfaceStyle),
+        ])
+
+        return .image(
+            layout: .device(config: deviceConfig),
+            traits: traits
+        )
+    }
+}

Tests/GravatarUITests/View+TestAdditions.swift

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+import SwiftUI
+
+extension View {
+    func markBounds() -> some View {
+        self
+            .padding(1) // to prevent borders from intersecting with content
+            .clipShape(RoundedRectangle(cornerSize: .zero))
+            .overlay(
+                RoundedRectangle(cornerSize: .zero)
+                    .stroke(.red, lineWidth: 1)
+            )
+    }
+}