content test: Test auth header in RealmContentNetworkImage

This gives us our first concrete tests of application code that uses
PerAccountStoreWidget, so #30 is complete.

Fixes: #30

Author: gnprice

test/widgets/content_test.dart

@@ -1,16 +1,124 @@
+import 'dart:async';
+import 'dart:io';
+
 import 'package:checks/checks.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
+import 'package:zulip/api/core.dart';
 import 'package:zulip/widgets/content.dart';
+import 'package:zulip/widgets/store.dart';
+
+import '../example_data.dart' as eg;
+import '../model/binding.dart';
 
 void main() {
-  testWidgets('Throws if no `PerAccountStoreWidget` ancestor', (WidgetTester tester) async {
-    await tester.pumpWidget(
-      const RealmContentNetworkImage('https://zulip.invalid/path/to/image.png', filterQuality: FilterQuality.medium));
-    check(tester.takeException()).isA<AssertionError>();
+  TestDataBinding.ensureInitialized();
+
+  group('RealmContentNetworkImage', () {
+    final authHeaders = authHeader(email: eg.selfAccount.email, apiKey: eg.selfAccount.apiKey);
+
+    Future<String?> actualAuthHeader(WidgetTester tester, String src) async {
+      final globalStore = TestDataBinding.instance.globalStore;
+      addTearDown(TestDataBinding.instance.reset);
+      await globalStore.add(eg.selfAccount, eg.initialSnapshot);
+
+      final httpClient = _FakeHttpClient();
+      debugNetworkImageHttpClientProvider = () => httpClient;
+      httpClient.request.response
+        ..statusCode = HttpStatus.ok
+        ..content = kSolidBlueAvatar;
+
+      await tester.pumpWidget(GlobalStoreWidget(
+        child: PerAccountStoreWidget(accountId: eg.selfAccount.id,
+          child: RealmContentNetworkImage(src))));
+      await tester.pump();
+      await tester.pump();
+
+      final headers = httpClient.request.headers.values;
+      check(authHeaders.keys).deepEquals(['Authorization']);
+      return headers['Authorization']?.single;
+    }
+
+    testWidgets('includes auth header if `src` on-realm', (tester) async {
+      check(await actualAuthHeader(tester, 'https://chat.example/image.png'))
+        .isNotNull().equals(authHeaders['Authorization']!);
+      debugNetworkImageHttpClientProvider = null;
+    });
+
+    testWidgets('excludes auth header if `src` off-realm', (tester) async {
+      check(await actualAuthHeader(tester, 'https://other.example/image.png'))
+        .isNull();
+      debugNetworkImageHttpClientProvider = null;
+    });
+
+    testWidgets('throws if no `PerAccountStoreWidget` ancestor', (WidgetTester tester) async {
+      await tester.pumpWidget(
+        const RealmContentNetworkImage('https://zulip.invalid/path/to/image.png', filterQuality: FilterQuality.medium));
+      check(tester.takeException()).isA<AssertionError>();
+    });
   });
+}
+
+class _FakeHttpClient extends Fake implements HttpClient {
+  final _FakeHttpClientRequest request = _FakeHttpClientRequest();
+
+  @override
+  Future<HttpClientRequest> getUrl(Uri url) async => request;
+}
+
+class _FakeHttpClientRequest extends Fake implements HttpClientRequest {
+  final _FakeHttpClientResponse response = _FakeHttpClientResponse();
 
-  // TODO(#30): Simulate a `PerAccountStoreWidget` ancestor, to use in more tests:
-  // TODO: 'Includes auth header if `src` is on-realm'
-  // TODO: 'Excludes auth header if `src` is off-realm'
+  @override
+  final _FakeHttpHeaders headers = _FakeHttpHeaders();
+
+  @override
+  Future<HttpClientResponse> close() async => response;
 }
+
+class _FakeHttpHeaders extends Fake implements HttpHeaders {
+  final Map<String, List<String>> values = {};
+
+  @override
+  void add(String name, Object value, {bool preserveHeaderCase = false}) {
+    (values[name] ??= []).add(value.toString());
+  }
+}
+
+class _FakeHttpClientResponse extends Fake implements HttpClientResponse {
+  @override
+  int statusCode = HttpStatus.ok;
+
+  late List<int> content;
+
+  @override
+  int get contentLength => content.length;
+
+  @override
+  HttpClientResponseCompressionState get compressionState => HttpClientResponseCompressionState.notCompressed;
+
+  @override
+  StreamSubscription<List<int>> listen(void Function(List<int> event)? onData, {Function? onError, void Function()? onDone, bool? cancelOnError}) {
+    return Stream.value(content).listen(
+      onData, onDone: onDone, onError: onError, cancelOnError: cancelOnError);
+  }
+}
+
+/// A 100x100 PNG image of solid Zulip blue, [kZulipBrandColor].
+// Made from the following SVG:
+//   <svg xmlns="http://www.w3.org/2000/svg" width="1" height="1" viewBox="0 0 1 1">
+//     <rect style="fill:#6492fe;fill-opacity:1" width="1" height="1" x="0" y="0" />
+//   </svg>
+// with `inkscape tmp.svg -w 100 --export-png=tmp1.png`,
+// `zopflipng tmp1.png tmp.png`,
+// and `xxd -i tmp.png`.
+const List<int> kSolidBlueAvatar = [
+  0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a, 0x00, 0x00, 0x00, 0x0d,
+  0x49, 0x48, 0x44, 0x52, 0x00, 0x00, 0x00, 0x64, 0x00, 0x00, 0x00, 0x64,
+  0x01, 0x03, 0x00, 0x00, 0x00, 0x4a, 0x2c, 0x07, 0x17, 0x00, 0x00, 0x00,
+  0x03, 0x50, 0x4c, 0x54, 0x45, 0x64, 0x92, 0xfe, 0xf1, 0xd6, 0x69, 0xa5,
+  0x00, 0x00, 0x00, 0x13, 0x49, 0x44, 0x41, 0x54, 0x78, 0x01, 0x63, 0xa0,
+  0x2b, 0x18, 0x05, 0xa3, 0x60, 0x14, 0x8c, 0x82, 0x51, 0x00, 0x00, 0x05,
+  0x78, 0x00, 0x01, 0x1e, 0xcd, 0x28, 0xcd, 0x00, 0x00, 0x00, 0x00, 0x49,
+  0x45, 0x4e, 0x44, 0xae, 0x42, 0x60, 0x82,
+];