feat: add Gemini and Spartan protocol support

app/test/browser_controller_test.dart

@@ -0,0 +1,103 @@
+import 'dart:io';
+
+import 'package:drift/native.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+import 'package:mews/application/controllers/browser_controller.dart';
+import 'package:mews/application/key_store.dart';
+import 'package:mews/database/database.dart';
+import 'package:mews/protocols/tofu.dart';
+
+import 'fake_fetch.dart';
+
+void main() {
+  late MewsDatabase db;
+  late Directory keyDir;
+  late KeyStore keys;
+
+  setUp(() async {
+    db = MewsDatabase.test(NativeDatabase.memory());
+    keyDir = await Directory.systemTemp.createTemp('mews-keys');
+    keys = KeyStore(() async => keyDir);
+  });
+
+  tearDown(() async {
+    await db.close();
+    keyDir.deleteSync(recursive: true);
+  });
+
+  BrowserController browser(FakeFetch fetch) =>
+      BrowserController(db: db, fetch: fetch, keys: keys);
+
+  test('a bare hostname that answers on gemini is found there', () async {
+    final controller =
+        browser(FakeFetch({'gemini://capsule.example': '# Hello\n\nText.'}));
+
+    await controller.open('capsule.example');
+
+    expect(controller.error.value, isNull);
+    expect(controller.currentPage.value!.url, 'gemini://capsule.example');
+    expect(controller.currentPage.value!.title, 'Hello');
+  });
+
+  test('a bare hostname that answers on spartan is found there', () async {
+    final controller =
+        browser(FakeFetch({'spartan://capsule.example': '# Hello\n\nText.'}));
+
+    await controller.open('capsule.example');
+
+    expect(controller.error.value, isNull);
+    expect(controller.currentPage.value!.url, 'spartan://capsule.example');
+  });
+
+  test('an explicit scheme is not second-guessed', () async {
+    final controller =
+        browser(FakeFetch({'gemini://capsule.example': '# Hello\n\nText.'}));
+
+    // The reader named the web, so a missing web page is an error, not an
+    // invitation to try the capsule protocols.
+    await controller.open('https://capsule.example');
+
+    expect(controller.error.value, isA<LoadFailed>());
+    expect(controller.currentPage.value, isNull);
+  });
+
+  test('a changed certificate blocks until the reader trusts the new one', () async {
+    final presented = TofuPin(fingerprint: 'new', expires: DateTime(2036));
+    final controller = browser(FakeFetch(
+      {'gemini://capsule.example': '# Hello\n\nText.'},
+      changedCertificates: {'gemini://capsule.example': presented},
+    ));
+
+    await controller.open('gemini://capsule.example');
+    expect(controller.error.value, isA<CertificateChanged>());
+
+    // Trusting records the presented certificate as the host's new pin.
+    await controller.trustPresentedCertificate();
+    expect(await db.allPins(), {'capsule.example:1965': presented});
+  });
+
+  test('a certificate request is answered by binding an identity', () async {
+    final controller = browser(FakeFetch(
+      {'gemini://capsule.example': '# Hello\n\nText.'},
+      certificateRequired: {'gemini://capsule.example'},
+    ));
+    final id = await db.addClientCertificate('Reader', 'CERT PEM');
+    await keys.save(id, 'KEY PEM');
+
+    // The site asks before anything shows; the reader's answer is a choice,
+    // not an automatic presentation.
+    await controller.open('gemini://capsule.example');
+    expect(controller.error.value, isA<ClientCertificateRequired>());
+
+    await controller.chooseCertificate(id);
+    expect(await db.bindingFor('capsule.example', 1965), id);
+    expect(controller.error.value, isNull);
+    expect(controller.currentPage.value!.title, 'Hello');
+
+    // The binding is worn on the next visit too, without asking again.
+    await controller.open('gemini://capsule.example');
+    expect(controller.error.value, isNull);
+    expect(controller.currentPage.value!.title, 'Hello');
+  });
+}