How to implement snapshot tests in SwiftUI

// ── Package.swift additions ────────────────────────────────────────
// dependencies:
//   .package(url: "https://github.com/pointfreeco/swift-snapshot-testing",
//            from: "1.17.0")
// targets (test target only):
//   .product(name: "SnapshotTesting", package: "swift-snapshot-testing")

import XCTest
import SnapshotTesting
import SwiftUI

// ── View under test ────────────────────────────────────────────────
struct ProfileCard: View {
    let name: String
    let role: String

    var body: some View {
        HStack(spacing: 16) {
            Image(systemName: "person.crop.circle.fill")
                .resizable()
                .frame(width: 56, height: 56)
                .foregroundStyle(.accent)
                .accessibilityLabel("Profile photo")
            VStack(alignment: .leading, spacing: 4) {
                Text(name)
                    .font(.headline)
                Text(role)
                    .font(.subheadline)
                    .foregroundStyle(.secondary)
            }
            Spacer()
        }
        .padding()
        .background(.regularMaterial, in: RoundedRectangle(cornerRadius: 16))
        .padding(.horizontal)
    }
}

// ── Snapshot test suite ────────────────────────────────────────────
final class ProfileCardSnapshotTests: XCTestCase {

    /// Flip to `true` to write/overwrite reference PNGs, then flip back.
    private let isRecording = false

    // 1. Light mode — iPhone 16 Pro width
    func testProfileCard_light() {
        let sut = ProfileCard(name: "Ada Lovelace", role: "Principal Engineer")
            .environment(\.colorScheme, .light)
        assertSnapshot(
            of: sut,
            as: .image(layout: .fixed(width: 393, height: 104)),
            record: isRecording
        )
    }

    // 2. Dark mode — separate reference PNG
    func testProfileCard_dark() {
        let sut = ProfileCard(name: "Ada Lovelace", role: "Principal Engineer")
            .environment(\.colorScheme, .dark)
        assertSnapshot(
            of: sut,
            as: .image(layout: .fixed(width: 393, height: 104)),
            record: isRecording
        )
    }

    // 3. Accessibility Extra Large Dynamic Type
    func testProfileCard_accessibilityXL() {
        let sut = ProfileCard(name: "Ada Lovelace", role: "Principal Engineer")
            .environment(\.sizeCategory, .accessibilityExtraLarge)
        assertSnapshot(
            of: sut,
            as: .image(layout: .fixed(width: 393, height: 180)),
            record: isRecording
        )
    }

    // 4. sizeThatFits — let SwiftUI measure its own intrinsic size
    func testProfileCard_intrinsicSize() {
        let sut = ProfileCard(name: "Jo", role: "Dev")
        assertSnapshot(
            of: sut,
            as: .image(layout: .sizeThatFits),
            record: isRecording
        )
    }
}

// ── SwiftUI Preview ────────────────────────────────────────────────
#Preview("Light") {
    ProfileCard(name: "Ada Lovelace", role: "Principal Engineer")
        .padding(.vertical)
}

#Preview("Dark") {
    ProfileCard(name: "Ada Lovelace", role: "Principal Engineer")
        .padding(.vertical)
        .preferredColorScheme(.dark)
}

func testProfileCard_multiDevice() {
    let devices: [(String, ViewImageConfig)] = [
        ("iPhoneSE3",   .iPhoneSe),
        ("iPhone16Pro", .iPhone13Pro),
        ("iPadPro11",   .iPadPro11)
    ]
    for (name, config) in devices {
        assertSnapshot(
            of: ProfileCard(name: "Ada Lovelace", role: "Engineer"),
            as: .image(layout: .device(config: config)),
            named: name,
            record: isRecording
        )
    }
}