test(mobile): exercise native signing in linked iOS Runner

Signed-off-by: Tom Brow <tomb@block.xyz>

.github/workflows/_ci-clients.yml

@@ -248,11 +248,18 @@ jobs:
           tail -n 5 "$build_log"
           "${xcode[@]}" -parallel-testing-enabled NO -only-testing:RunnerTests \
             test-without-building
+          /bin/bash scripts/test-mobile-linked-signing.sh "$device"
       - name: Build complete unsigned iOS release
         if: matrix.lane == 'release'
         run: |
           /bin/bash scripts/test-mobile-gateway-recipes.sh
           cd mobile && flutter build ios --release --no-codesign --no-pub
+          # Flutter does not support Release mode on the simulator. Check the
+          # actual device Release executable's exported symbols separately.
+          nm -gU build/ios/iphoneos/Buzz.app/Buzz > /tmp/buzz-release-symbols
+          for symbol in buzz_signer_create buzz_signer_sign buzz_signer_destroy; do
+            grep -Eq "[[:space:]]_${symbol}$" /tmp/buzz-release-symbols
+          done
 
   results:
     name: Results

mobile/tool/native_signing_probe.dart

@@ -1,4 +1,5 @@
 import 'dart:convert';
+import 'dart:io';
 import 'package:flutter/material.dart';
 import 'package:nostr/nostr.dart' as nostr;
 import 'package:buzz/shared/relay/media_auth.dart';
@@ -7,6 +8,7 @@ import 'package:buzz/shared/crypto/event_signer.dart';
 
 Future<void> main() async {
   WidgetsFlutterBinding.ensureInitialized();
+  if (!Platform.isIOS) throw StateError('This probe requires an iOS Runner');
   final results = <String>[];
   final key = '0' * 63 + '3';
   final nsec = nostr.Nip19.encode(prefix: nostr.Nip19Prefix.nsec, data: key);
@@ -86,12 +88,16 @@ Future<void> main() async {
     '32 complete NIP98 headers: ${queryWatch.elapsedMicroseconds} us',
   );
   for (final header in headers) {
-    nostr.Event.fromJson(utf8.decode(base64Decode(header.split(' ').last)));
+    final event = nostr.Event.fromJson(
+      utf8.decode(base64Decode(header.split(' ').last)),
+    );
+    if (!event.isValid()) throw StateError('Invalid query proof');
   }
   results.add('query signatures: PASS');
   for (final result in results) {
     debugPrint('SIGNING_PROBE $result');
   }
+  debugPrint('SIGNING_PROBE COMPLETE');
   runApp(
     MaterialApp(
       home: Scaffold(body: SafeArea(child: Text(results.join('\n')))),

scripts/test-mobile-linked-signing.sh

@@ -0,0 +1,35 @@
+#!/usr/bin/env bash
+# Run the Dart production signer through symbols exported by the actual Runner.
+set -euo pipefail
+cd "$(dirname "$0")/.."
+. ./bin/activate-hermit
+device=${1:?Pass a booted simulator UDID}
+fixture=$(mktemp -d)
+bundle=xyz.block.buzz.signing-probe
+trap 'xcrun simctl terminate "$device" "$bundle" >/dev/null 2>&1 || true; rm -rf "$fixture"' EXIT
+xcodebuild -workspace mobile/ios/Runner.xcworkspace -scheme Runner \
+  -configuration Debug -sdk iphonesimulator -destination "id=$device" \
+  -derivedDataPath "${BUZZ_SIGNING_DERIVED_DATA:-$fixture/build}" -jobs 2 \
+  BUNDLE_IDENTIFIER="$bundle" CODE_SIGNING_ALLOWED=NO ONLY_ACTIVE_ARCH=YES \
+  FLUTTER_TARGET=tool/native_signing_probe.dart build > "$fixture/build.log" 2>&1 || {
+    cat "$fixture/build.log"
+    exit 1
+  }
+xcrun simctl install "$device" "${BUZZ_SIGNING_DERIVED_DATA:-$fixture/build}/Build/Products/Debug-iphonesimulator/Buzz.app"
+launch=$(xcrun simctl launch --terminate-running-process "$device" "$bundle")
+probe_pid=${launch##*: }
+[[ "$probe_pid" =~ ^[0-9]+$ ]] || { echo "Unexpected launch result: $launch" >&2; exit 1; }
+# Flutter's iOS logger writes to the unified log, not redirected stdout.
+for ((attempt = 0; attempt < 90; attempt++)); do
+  xcrun simctl spawn "$device" log show --last 5m --style compact \
+    --predicate "processIdentifier == $probe_pid AND eventMessage CONTAINS \"SIGNING_PROBE\"" \
+    > "$fixture/probe.log" 2>/dev/null
+  if grep -q 'SIGNING_PROBE COMPLETE' "$fixture/probe.log"; then
+    cat "$fixture/probe.log"
+    exit 0
+  fi
+  sleep 1
+done
+cat "$fixture/probe.log"
+echo 'Linked iOS signing probe did not complete' >&2
+exit 1