Improve tests.

Author: VelikovPetar

stream-chat-android-client/src/main/java/io/getstream/chat/android/client/parser2/direct/JsonParsingUtils.kt

@@ -25,6 +25,7 @@ import kotlin.contracts.contract
 /**
  * Utility functions for parsing JSON with consistent null-handling.
  */
+@Suppress("TooManyFunctions")
 internal object JsonParsingUtils {
 
     /**
@@ -40,6 +41,21 @@ internal object JsonParsingUtils {
         )
     }
 
+    /**
+     * Throws [JsonDataException] if the next JSON value is an explicit `null`. Use for fields
+     * whose DTO declaration is non-nullable but has a default value — Moshi codegen rejects
+     * explicit JSON null for such fields, so we mirror that for parser parity. Fields that are
+     * absent altogether do not reach this check (the surrounding `when` branch isn't entered),
+     * which preserves the default-on-missing behavior.
+     */
+    fun rejectExplicitNull(reader: JsonReader, fieldName: String) {
+        if (reader.peek() == JsonReader.Token.NULL) {
+            throw JsonDataException(
+                "Non-null value '$fieldName' was null at ${reader.path}",
+            )
+        }
+    }
+
     /** Reads a nullable Int (returns null if JSON value is null). */
     fun readNullableInt(reader: JsonReader): Int? {
         return if (reader.peek() == JsonReader.Token.NULL) reader.nextNull() else reader.nextInt()

stream-chat-android-client/src/main/java/io/getstream/chat/android/client/parser2/direct/MessageAdapter.kt

@@ -111,7 +111,12 @@ internal class MessageAdapter(
                 "created_at" -> createdAt = dateAdapter.fromJson(reader)
                 "deleted_at" -> deletedAt = dateAdapter.fromJson(reader)
                 "html" -> html = reader.nextString()
-                "i18n" -> i18n = JsonParsingUtils.parseStringMap(reader)
+                // i18n is non-nullable in DownstreamMessageDto (with default), so the DTO path
+                // throws on explicit JSON null even though missing is fine. Match that here.
+                "i18n" -> {
+                    JsonParsingUtils.rejectExplicitNull(reader, "i18n")
+                    i18n = JsonParsingUtils.parseStringMap(reader)
+                }
                 "id" -> id = reader.nextString()
                 "latest_reactions" -> latestReactions = JsonParsingUtils.parseList(reader, reactionAdapter)
                 "mentioned_users" -> mentionedUsers = JsonParsingUtils.parseList(reader, userAdapter)
@@ -138,7 +143,12 @@ internal class MessageAdapter(
                 "show_in_channel" -> showInChannel = reader.nextBoolean()
                 "silent" -> silent = reader.nextBoolean()
                 "text" -> text = reader.nextString()
-                "thread_participants" -> threadParticipants = JsonParsingUtils.parseList(reader, userAdapter)
+                // thread_participants is non-nullable in DownstreamMessageDto (with default),
+                // so the DTO path throws on explicit JSON null. Match that here.
+                "thread_participants" -> {
+                    JsonParsingUtils.rejectExplicitNull(reader, "thread_participants")
+                    threadParticipants = JsonParsingUtils.parseList(reader, userAdapter)
+                }
                 "type" -> type = reader.nextString()
                 "updated_at" -> updatedAt = dateAdapter.fromJson(reader)
                 "user" -> user = userAdapter.fromJson(reader)

stream-chat-android-client/src/test/java/io/getstream/chat/android/client/parser2/DirectEventParserTest.kt

@@ -16,10 +16,14 @@
 
 package io.getstream.chat.android.client.parser2
 
+import io.getstream.chat.android.client.api2.mapping.DomainMapping
+import io.getstream.chat.android.client.api2.mapping.EventMapping
+import io.getstream.chat.android.client.api2.model.dto.NewMessageEventDto
 import io.getstream.chat.android.client.events.NewMessageEvent
 import io.getstream.chat.android.client.parser2.DirectEventParser.Companion.extractType
 import io.getstream.chat.android.client.parser2.testdata.NewMessageEventTestData
 import io.getstream.chat.android.models.MessageTransformer
+import io.getstream.chat.android.models.NoOpChannelTransformer
 import io.getstream.chat.android.models.NoOpMessageTransformer
 import io.getstream.chat.android.models.NoOpUserTransformer
 import io.getstream.chat.android.models.UserTransformer
@@ -90,7 +94,30 @@ internal class DirectEventParserTest {
         fun `returns NewMessageEvent for message_new type`() {
             val event = parser.parse(NewMessageEventTestData.jsonAllFields)
             assertTrue(event is NewMessageEvent)
-            assertEquals(NewMessageEventTestData.expectedAllFields, event)
+        }
+
+        @Test
+        fun `direct path produces the same NewMessageEvent as the DTO path`() {
+            // Parity check: the DirectEventParser output must match what the legacy
+            // JSON → NewMessageEventDto → toDomain() pipeline produces for the same JSON.
+            val moshiChatParser = ParserFactory.createMoshiChatParser()
+            val eventMapping = EventMapping(
+                DomainMapping(
+                    currentUserIdProvider = { "" },
+                    channelTransformer = NoOpChannelTransformer,
+                    messageTransformer = NoOpMessageTransformer,
+                    userTransformer = NoOpUserTransformer,
+                ),
+            )
+
+            val directResult = parser.parse(NewMessageEventTestData.jsonAllFields)
+            val dtoResult = with(eventMapping) {
+                moshiChatParser
+                    .fromJson(NewMessageEventTestData.jsonAllFields, NewMessageEventDto::class.java)
+                    .toDomain()
+            }
+
+            assertEquals(dtoResult, directResult)
         }
 
         @Test