populate_db: Generate topics using config fixture.

Instread of using stream_name + Intergers as topics, we now
generate topics using pos in `config.generate_data.json`.

This helps us create and test more realistic topics.

zerver/lib/generate_test_data.py

@@ -12,6 +12,29 @@ def load_config() -> Dict[str, Any]:
 
     return config
 
+def generate_topics(num_topics: int) -> List[str]:
+    config = load_config()["gen_fodder"]
+
+    topics = []
+    # Make single word topics account for 30% of total topics.
+    # Single word topics are most common, thus
+    # it is important we test on it.
+    num_single_word_topics = num_topics // 3
+    for _ in itertools.repeat(None, num_single_word_topics):
+        topics.append(random.choice(config["nouns"]))
+
+    sentence = ["adjectives", "nouns", "connectors", "verbs", "adverbs"]
+    for pos in sentence:
+        # Add an empty string so that we can generate variable length topics.
+        config[pos].append("")
+
+    for _ in itertools.repeat(None, num_topics - num_single_word_topics):
+        generated_topic = [random.choice(config[pos]) for pos in sentence]
+        topic = " ".join(filter(None, generated_topic))
+        topics.append(topic)
+
+    return topics
+
 def load_generators(config: Dict[str, Any]) -> Dict[str, Any]:
 
     results = {}

zilencer/management/commands/populate_db.py

@@ -20,7 +20,7 @@ from zerver.lib.actions import STREAM_ASSIGNMENT_COLORS, check_add_realm_emoji,
     try_add_realm_custom_profile_field, try_add_realm_default_custom_profile_field
 from zerver.lib.bulk_create import bulk_create_streams
 from zerver.lib.cache import cache_set
-from zerver.lib.generate_test_data import create_test_data
+from zerver.lib.generate_test_data import create_test_data, generate_topics
 from zerver.lib.onboarding import create_if_missing_realm_internal_bots
 from zerver.lib.push_notifications import logger as push_notifications_logger
 from zerver.lib.server_initialization import create_internal_realm, create_users
@@ -648,6 +648,11 @@ def generate_and_send_messages(data: Tuple[int, Sequence[Sequence[int]], Mapping
         huddle_members[h] = [s.user_profile.id for s in
                              Subscription.objects.filter(recipient_id=h)]
 
+    # Generate different topics for each stream
+    possible_topics = dict()
+    for stream_id in recipient_streams:
+        possible_topics[stream_id] = generate_topics(options["max_topics"])
+
     message_batch_size = options['batch_size']
     num_messages = 0
     random_max = 1000000
@@ -693,11 +698,10 @@ def generate_and_send_messages(data: Tuple[int, Sequence[Sequence[int]], Mapping
             message.sender = get_user_profile_by_id(personals_pair[1])
             saved_data['personals_pair'] = personals_pair
         elif message_type == Recipient.STREAM:
-            stream = Stream.objects.get(id=message.recipient.type_id)
             # Pick a random subscriber to the stream
             message.sender = random.choice(Subscription.objects.filter(
                 recipient=message.recipient)).user_profile
-            message.subject = stream.name + str(random.randint(1, options["max_topics"]))
+            message.subject = random.choice(possible_topics[message.recipient.id])
             saved_data['subject'] = message.subject
 
         message.date_sent = choose_date_sent(num_messages, tot_messages, options['threads'])