compose_box test: Set topic and content through a helper

This ensures that the `GetStreamTopicsResult` is self-contained, so
that the caller does not rely on the assumption that a response has
been prepared through `prepareComposeBox`.

This also elevates contentInputFinder for reuse throughout the test.

This changes the way the tests work, because now we use tester.enterText
to set the topic and content, instead of accessing the controllers.

Signed-off-by: Zixuan James Li <[email protected]>

Author: PIG208

test/widgets/compose_box_test.dart

@@ -32,8 +32,18 @@ void main() {
   late PerAccountStore store;
   late FakeApiConnection connection;
 
-  Future<GlobalKey<ComposeBoxController>> prepareComposeBox(WidgetTester tester,
-      {required Narrow narrow, List<User> users = const []}) async {
+  final topicInputFinder = find.byWidgetPredicate(
+    (widget) => widget is TextField && widget.controller is ComposeTopicController);
+  final contentInputFinder = find.byWidgetPredicate(
+    (widget) => widget is TextField && widget.controller is ComposeContentController);
+
+  Future<GlobalKey<ComposeBoxController>> prepareComposeBox(
+    WidgetTester tester, {
+    required Narrow narrow,
+    String? topic,
+    String? content,
+    List<User> users = const [],
+  }) async {
     addTearDown(testBinding.reset);
     await testBinding.globalStore.add(eg.selfAccount, eg.initialSnapshot());
 
@@ -42,16 +52,26 @@ void main() {
     await store.addUsers([eg.selfUser, ...users]);
     connection = store.connection as FakeApiConnection;
 
-    if (narrow is ChannelNarrow) {
-      // Ensure topics are loaded before testing actual logic.
-      connection.prepare(body:
-        jsonEncode(GetStreamTopicsResult(topics: [eg.getStreamTopicsEntry()]).toJson()));
-    }
     final controllerKey = GlobalKey<ComposeBoxController>();
     await tester.pumpWidget(TestZulipApp(accountId: eg.selfAccount.id,
       child: ComposeBox(controllerKey: controllerKey, narrow: narrow)));
     await tester.pumpAndSettle();
 
+    if (topic != null) {
+      // The topic input is currently only available to ChannelNarrow.
+      narrow as ChannelNarrow;
+      connection.prepare(body:
+        jsonEncode(GetStreamTopicsResult(topics: [eg.getStreamTopicsEntry()]).toJson()));
+      await tester.enterText(topicInputFinder, topic);
+      check(connection.takeRequests()).single
+        ..method.equals('GET')
+        ..url.path.equals('/api/v1/users/me/${narrow.streamId}/topics');
+    }
+    if (content != null) {
+      await tester.enterText(contentInputFinder, content);
+    }
+    await tester.pump();
+
     return controllerKey;
   }
 
@@ -206,8 +226,6 @@ void main() {
       final zulipLocalizations = GlobalLocalizations.zulipLocalizations;
       await prepareComposeBox(tester, narrow: const TopicNarrow(123, 'some topic'));
 
-      final contentInputFinder = find.byWidgetPredicate(
-        (widget) => widget is TextField && widget.controller is ComposeContentController);
       await tester.enterText(contentInputFinder, 'hello world');
 
       prepareResponse(456);
@@ -271,14 +289,12 @@ void main() {
         TypingNotifier.debugEnable = false;
         addTearDown(TypingNotifier.debugReset);
 
-        final controllerKey = await prepareComposeBox(tester, narrow: ChannelNarrow(eg.stream().streamId));
+        final controllerKey = await prepareComposeBox(tester,
+          narrow: ChannelNarrow(eg.stream().streamId),
+          topic: 'some topic', content: 'see image: ');
         final composeBoxController = controllerKey.currentState!;
-
         // (When we check that the send button looks disabled, it should be because
         // the file is uploading, not a pre-existing reason.)
-        composeBoxController.topicController!.value = const TextEditingValue(text: 'some topic');
-        composeBoxController.contentController.value = const TextEditingValue(text: 'see image: ');
-        await tester.pump();
         checkAppearsLoading(tester, false);
 
         testBinding.pickFilesResult = FilePickerResult([PlatformFile(
@@ -330,14 +346,12 @@ void main() {
         TypingNotifier.debugEnable = false;
         addTearDown(TypingNotifier.debugReset);
 
-        final controllerKey = await prepareComposeBox(tester, narrow: ChannelNarrow(eg.stream().streamId));
+        final controllerKey = await prepareComposeBox(tester,
+          narrow: ChannelNarrow(eg.stream().streamId),
+          topic: 'some topic', content: 'see image: ');
         final composeBoxController = controllerKey.currentState!;
-
         // (When we check that the send button looks disabled, it should be because
         // the file is uploading, not a pre-existing reason.)
-        composeBoxController.topicController!.value = const TextEditingValue(text: 'some topic');
-        composeBoxController.contentController.value = const TextEditingValue(text: 'see image: ');
-        await tester.pump();
         checkAppearsLoading(tester, false);
 
         testBinding.pickImageResult = XFile.fromData(