1 files changed, 65 insertions, 0 deletions
diff --git a/formats/protobuf/jvmTest/src/kotlinx/serialization/protobuf/conformance/Proto3MessageTest.kt b/formats/protobuf/jvmTest/src/kotlinx/serialization/protobuf/conformance/Proto3MessageTest.kt
new file mode 100644
index 00000000..c369d6eb
--- /dev/null
+++ b/formats/protobuf/jvmTest/src/kotlinx/serialization/protobuf/conformance/Proto3MessageTest.kt
@@ -0,0 +1,65 @@
+/*
+ * Copyright 2017-2023 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
+ */
+
+package kotlinx.serialization.protobuf.conformance
+
+import com.google.protobuf_test_messages.proto3.*
+import kotlinx.serialization.*
+import kotlinx.serialization.protobuf.*
+import kotlin.test.*
+
+@Serializable
+data class KTestMessagesProto3Message(
+    @ProtoNumber(18) val optionalNestedMessage: KNestedMessage? = null,
+    @ProtoNumber(19) val optionalForeignMessage: KForeignMessage? = null,
+) {
+    @Serializable
+    data class KNestedMessage(
+        @ProtoNumber(1) val a: Int = 0,
+        @ProtoNumber(2) val corecursive: KTestMessagesProto3Message? = null,
+    ) {
+        fun toProto(): TestMessagesProto3.TestAllTypesProto3.NestedMessage =
+            TestMessagesProto3.TestAllTypesProto3.NestedMessage.parseFrom(
+                ProtoBuf.encodeToByteArray(this)
+            )
+    }
+}
+
+@Serializable
+data class KForeignMessage(
+    @ProtoNumber(1) val c: Int = 0,
+) {
+    fun toProto(): TestMessagesProto3.ForeignMessage =
+        TestMessagesProto3.ForeignMessage.parseFrom(
+            ProtoBuf.encodeToByteArray(this)
+        )
+}
+
+class Proto3MessageTest {
+    @Test
+    fun default() {
+        val message = KTestMessagesProto3Message(
+            optionalNestedMessage = KTestMessagesProto3Message.KNestedMessage(
+                a = 150,
+                corecursive = KTestMessagesProto3Message(
+                    optionalNestedMessage = KTestMessagesProto3Message.KNestedMessage(
+                        a = 42,
+                    )
+                )
+            ),
+            optionalForeignMessage = KForeignMessage(
+                c = 150,
+            )
+        )
+
+        val bytes = ProtoBuf.encodeToByteArray(message)
+        val restored = TestMessagesProto3.TestAllTypesProto3.parseFrom(bytes)
+        assertEquals(message.optionalNestedMessage?.a, restored.optionalNestedMessage.a)
+        assertEquals(
+            message.optionalNestedMessage?.corecursive?.optionalNestedMessage?.a,
+            restored.optionalNestedMessage.corecursive.optionalNestedMessage.a
+        )
+        assertEquals(message.optionalForeignMessage?.c, restored.optionalForeignMessage.c)
+    }
+}