[Serialization] Reorganize module structure

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

@@ -0,0 +1,51 @@
+// WITH_STDLIB
+
+import kotlinx.serialization.*
+import kotlinx.serialization.descriptors.*
+import kotlinx.serialization.json.*
+
+@Serializable
+sealed interface I
+
+@Serializable
+sealed class X: I {
+    private var x = "X"
+
+    fun exposeX() = x
+}
+
+@Serializable
+abstract class Y: X() {
+    private var y = "Y"
+
+    fun exposeY() = y
+}
+
+@Serializable
+class Bottom: Y()
+
+fun testData(results: String): String {
+    if (results != "OK") return results
+    val serial = Bottom.serializer()
+    val j = Json { encodeDefaults = true }
+    val s = j.encodeToString(serial, Bottom())
+    if (s != """{"x":"X","y":"Y"}""") return "Incorrect encoding: $s"
+    val decoded = j.decodeFromString(serial, """{"x":"1","y":"2"}""")
+    if (decoded.exposeX() != "1") return "Incorrect X"
+    if (decoded.exposeY() != "2") return "Incorrect Y"
+    return "OK"
+}
+
+@OptIn(ExperimentalSerializationApi::class)
+fun testKinds(): String {
+    if (I.serializer().descriptor.kind != PolymorphicKind.SEALED) return "Not sealed: I"
+    if (X.serializer().descriptor.kind != PolymorphicKind.SEALED) return "Not sealed: X"
+    if (Y.serializer().descriptor.kind != PolymorphicKind.OPEN) return "Not polymorphic: Y"
+    val serial = Bottom.serializer()
+    if (serial.descriptor.kind != StructureKind.CLASS) return "Not class: Bottom"
+    return "OK"
+}
+
+fun box(): String {
+    return testData(testKinds())
+}