Added test on Serializable(with=...) in K2

plugins/kotlinx-serialization/testData/firMembers/serializableWith.kt

@@ -0,0 +1,56 @@
+// WITH_STDLIB
+
+import kotlinx.serialization.*
+import kotlinx.serialization.json.*
+import kotlinx.serialization.encoding.*
+import kotlinx.serialization.descriptors.*
+
+
+object IntHolderAsStringSerializer : KSerializer<IntHolder> {
+    override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("IntHolder", PrimitiveKind.STRING)
+
+    override fun serialize(encoder: Encoder, value: IntHolder) {
+        encoder.encodeString(value.value.toString())
+    }
+
+    override fun deserialize(decoder: Decoder): IntHolder {
+        val string = decoder.decodeString()
+        return IntHolder(string.toInt())
+    }
+}
+
+object ObjectSerializer : KSerializer<SerializableObject> {
+    override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("SerializableObject", PrimitiveKind.STRING)
+
+    override fun serialize(encoder: Encoder, value: SerializableObject) {
+        encoder.encodeString("obj")
+    }
+
+    override fun deserialize(decoder: Decoder): SerializableObject {
+        decoder.decodeString()
+        return SerializableObject
+    }
+}
+
+@Serializable(with = IntHolderAsStringSerializer::class)
+class IntHolder(val value: Int)
+
+@Serializable(with = ObjectSerializer::class)
+object SerializableObject
+
+fun box(): String {
+    val holder = IntHolder(42)
+
+    val encoded = Json.encodeToString(IntHolder.serializer(), holder)
+    if (encoded != "\"42\"") return encoded
+    val decoded = Json.decodeFromString(IntHolder.serializer(), encoded)
+    if (decoded.value != holder.value) return "Incorrect value"
+
+    val encodedObject = Json.encodeToString(SerializableObject.serializer(), SerializableObject)
+    if (encodedObject != "\"obj\"") return encodedObject
+    val decodedObject = Json.decodeFromString(SerializableObject.serializer(), encodedObject)
+    if (decodedObject != SerializableObject) return "Incorrect object instance"
+
+
+    return "OK"
+}