Watch: snapshot tests render the complication and multi-select screenshots

ImageRenderer draws the real views with demo data, since the watch simulator
is not drivable here. README covers the widget target and how to add it.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

watch/WristCodeTests/SnapshotTests.swift

@@ -0,0 +1,97 @@
+// Renders screens with demo data to PNGs in watch/screenshots. Skipped unless WC_SCREENSHOT_DIR is
+// set, which xcodebuild passes through from TEST_RUNNER_WC_SCREENSHOT_DIR:
+//
+//   TEST_RUNNER_WC_SCREENSHOT_DIR=$PWD/screenshots xcodebuild ... test -only-testing:WristCodeTests/SnapshotTests
+
+import ImageIO
+import SwiftUI
+import Testing
+import UniformTypeIdentifiers
+import WidgetKit
+@testable import WristCode
+
+private let outputDirectory = ProcessInfo.processInfo.environment["WC_SCREENSHOT_DIR"]
+
+/// The Series 12 (46mm) screen in points.
+private let screen = CGSize(width: 208, height: 248)
+
+@MainActor @Suite(.enabled(if: outputDirectory != nil))
+struct SnapshotTests {
+    @Test func complication() async throws {
+        let gateway = DemoGateway()
+        let waiting = WaitingEntry(date: .now, content: .counts(try await gateway.summary(), stale: false))
+        let feed = try await gateway.feed()
+        for item in feed.needsYou {
+            try await gateway.respond(
+                hostId: item.hostId, threadId: item.threadId,
+                request: .decision(requestId: item.request!.id, decision: .decline))
+        }
+        let idle = WaitingEntry(date: .now, content: .counts(try await gateway.summary(), stale: false))
+
+        try write(ComplicationGallery(waiting: waiting, idle: idle), "complication.png")
+    }
+
+    @Test func multiSelectQuestion() async throws {
+        let detail = try await DemoGateway().thread(hostId: "mac-mini", threadId: "t-release")
+        let view = ThreadView(
+            hostId: "mac-mini", threadId: "t-release", detail: detail,
+            selections: ["checks": ["unit", "lint"]], scrolls: false)
+            .environment(AppModel.preview())
+            .fontDesign(.rounded)
+            .tint(Theme.work)
+        try write(view, "thread-multiselect.png")
+    }
+
+    /// Renders at the screen's width and as tall as the content, as if scrolled through.
+    private func write(_ view: some View, _ name: String) throws {
+        let renderer = ImageRenderer(content: view
+            .frame(width: screen.width)
+            .fixedSize(horizontal: false, vertical: true)
+            .padding(.bottom, 8)
+            .background(.black)
+            .environment(\.colorScheme, .dark))
+        renderer.scale = 2
+        let image = try #require(renderer.cgImage)
+        let url = URL(fileURLWithPath: try #require(outputDirectory)).appending(path: name)
+        let destination = try #require(CGImageDestinationCreateWithURL(url as CFURL, UTType.png.identifier as CFString, 1, nil))
+        CGImageDestinationAddImage(destination, image, nil)
+        #expect(CGImageDestinationFinalize(destination))
+    }
+}
+
+/// Every family at its 46mm size, once with threads waiting and once with nothing waiting.
+private struct ComplicationGallery: View {
+    var waiting: WaitingEntry
+    var idle: WaitingEntry
+
+    var body: some View {
+        VStack(alignment: .leading, spacing: 10) {
+            section("3 waiting", waiting)
+            section("Nothing waiting", idle)
+        }
+        .padding(.horizontal, 10)
+        .padding(.top, 8)
+        .foregroundStyle(.white)
+    }
+
+    private func section(_ title: String, _ entry: WaitingEntry) -> some View {
+        VStack(alignment: .leading, spacing: 6) {
+            Text(title.uppercased())
+                .font(.system(size: 10, weight: .semibold, design: .rounded))
+                .foregroundStyle(Theme.done)
+            WaitingView(entry: entry, familyOverride: .accessoryInline)
+                .font(.system(size: 13, weight: .semibold, design: .rounded))
+                .frame(height: 18)
+            WaitingView(entry: entry, familyOverride: .accessoryRectangular)
+                .frame(width: 184, height: 72)
+            HStack(spacing: 16) {
+                // Outside a face AccessoryWidgetBackground fills a square; a face clips it round.
+                WaitingView(entry: entry, familyOverride: .accessoryCircular)
+                    .frame(width: 50, height: 50)
+                    .clipShape(Circle())
+                WaitingView(entry: entry, familyOverride: .accessoryCorner)
+                    .frame(width: 50, height: 50)
+            }
+        }
+    }
+}