autocomplete test [nfc]: Use deepEquals and conditions for end-to-end test

This will make it more smoothly generalize to situations where
different types of results are more intermingled.

Author: gnprice

test/model/autocomplete_checks.dart

@@ -1,6 +1,7 @@
 import 'package:checks/checks.dart';
 import 'package:zulip/api/model/model.dart';
 import 'package:zulip/model/autocomplete.dart';
+import 'package:zulip/model/compose.dart';
 import 'package:zulip/widgets/compose_box.dart';
 
 extension ComposeContentControllerChecks on Subject<ComposeContentController> {
@@ -20,6 +21,10 @@ extension UserMentionAutocompleteResultChecks on Subject<UserMentionAutocomplete
   Subject<int> get userId => has((r) => r.userId, 'userId');
 }
 
+extension WildcardMentionAutocompleteResultChecks on Subject<WildcardMentionAutocompleteResult> {
+  Subject<WildcardMentionOption> get wildcardOption => has((x) => x.wildcardOption, 'wildcardOption');
+}
+
 extension TopicAutocompleteResultChecks on Subject<TopicAutocompleteResult> {
   Subject<TopicName> get topic => has((r) => r.topic, 'topic');
 }

test/model/autocomplete_test.dart

@@ -813,11 +813,15 @@ void main() {
         return results;
       }
 
-      Iterable<int> getUsersFromResults(Iterable<MentionAutocompleteResult> results)
-        => results.map((e) => (e as UserMentionAutocompleteResult).userId);
+      Condition<Object?> isUser(int userId) {
+        return (it) => it.isA<UserMentionAutocompleteResult>()
+          .userId.equals(userId);
+      }
 
-      Iterable<WildcardMentionOption> getWildcardOptionsFromResults(Iterable<MentionAutocompleteResult> results)
-        => results.map((e) => (e as WildcardMentionAutocompleteResult).wildcardOption);
+      Condition<Object?> isWildcard(WildcardMentionOption option) {
+        return (it) => it.isA<WildcardMentionAutocompleteResult>()
+          .wildcardOption.equals(option);
+      }
 
       final stream = eg.stream();
       const topic = 'topic';
@@ -848,20 +852,21 @@ void main() {
       // 3. Users most recent in the DM conversations.
       // 4. Human vs. Bot users (human users come first).
       // 5. Users by name alphabetical order.
-      final results1 = await getResults(topicNarrow, MentionAutocompleteQuery(''));
-      check(getWildcardOptionsFromResults(results1.take(2)))
-        .deepEquals([WildcardMentionOption.all, WildcardMentionOption.topic]);
-      check(getUsersFromResults(results1.skip(2)))
-        .deepEquals([1, 5, 4, 2, 7, 3, 6]);
+      check(await getResults(topicNarrow, MentionAutocompleteQuery(''))).deepEquals([
+        isWildcard(WildcardMentionOption.all),
+        isWildcard(WildcardMentionOption.topic),
+        ...[1, 5, 4, 2, 7, 3, 6].map(isUser),
+      ]);
 
       // Check the ranking applies also to results filtered by a query.
-      final results2 = await getResults(topicNarrow, MentionAutocompleteQuery('t'));
-      check(getWildcardOptionsFromResults(results2.take(2)))
-        .deepEquals([WildcardMentionOption.stream, WildcardMentionOption.topic]);
-      check(getUsersFromResults(results2.skip(2))).deepEquals([2, 3]);
-      final results3 = await getResults(topicNarrow, MentionAutocompleteQuery('f'));
-      check(getWildcardOptionsFromResults(results3.take(0))).deepEquals([]);
-      check(getUsersFromResults(results3.skip(0))).deepEquals([5, 4]);
+      check(await getResults(topicNarrow, MentionAutocompleteQuery('t'))).deepEquals([
+        isWildcard(WildcardMentionOption.stream),
+        isWildcard(WildcardMentionOption.topic),
+        isUser(2), isUser(3),
+      ]);
+      check(await getResults(topicNarrow, MentionAutocompleteQuery('f'))).deepEquals([
+        isUser(5), isUser(4),
+      ]);
     });
   });