1 files changed, 100 insertions, 0 deletions
diff --git a/core/commonTest/src/kotlinx/serialization/features/SealedInterfacesSerializationTest.kt b/core/commonTest/src/kotlinx/serialization/features/SealedInterfacesSerializationTest.kt
new file mode 100644
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+++ b/core/commonTest/src/kotlinx/serialization/features/SealedInterfacesSerializationTest.kt
@@ -0,0 +1,100 @@
+/*
+ * Copyright 2017-2021 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
+ */
+
+@file:Suppress("SERIALIZER_TYPE_INCOMPATIBLE")
+
+package kotlinx.serialization.features
+
+import kotlinx.serialization.*
+import kotlinx.serialization.descriptors.*
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+import kotlinx.serialization.test.*
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+
+class SealedInterfacesSerializationTest {
+    interface A
+
+    sealed interface B
+
+    @Serializable
+    sealed interface C
+
+    @Serializable(DummySerializer::class)
+    sealed interface D
+
+    @Serializable(DummySerializer::class)
+    interface E
+
+    @Serializable
+    @Polymorphic
+    sealed interface F
+
+    @Serializable
+    class ImplA : A, B, C, D, E, F
+
+    @Serializable
+    class ImplB : A, B, C, D, E, F
+
+    @Serializable
+    class Holder(
+        val a: A,
+        val b: B,
+        val c: C,
+        val d: D,
+        val e: E,
+        @Polymorphic val polyC: C,
+        val f: F
+    )
+
+    class DummySerializer : KSerializer<Any> {
+        override val descriptor: SerialDescriptor = buildClassSerialDescriptor("Dummy")
+
+        override fun serialize(encoder: Encoder, value: Any) {
+            error("serialize")
+        }
+
+        override fun deserialize(decoder: Decoder): Any {
+            error("deserialize")
+        }
+    }
+
+    private fun SerialDescriptor.haveSealedSubclasses() {
+        assertEquals(PolymorphicKind.SEALED, kind)
+        val subclasses = getElementDescriptor(1).elementDescriptors.map { it.serialName.substringAfterLast('.') }
+        assertEquals(listOf("ImplA", "ImplB"), subclasses)
+    }
+
+    private fun SerialDescriptor.isDummy() = serialName == "Dummy"
+
+    private fun SerialDescriptor.isPolymorphic() = kind == PolymorphicKind.OPEN
+
+    operator fun SerialDescriptor.get(i: Int) = getElementDescriptor(i)
+
+    @Test
+    fun testInHolder() {
+        val desc = Holder.serializer().descriptor
+        desc[0].isPolymorphic()
+        desc[1].isPolymorphic()
+        desc[2].haveSealedSubclasses()
+        desc[3].isDummy()
+        desc[4].isDummy()
+        desc[5].isPolymorphic()
+        desc[6].isPolymorphic()
+    }
+
+    @Test
+    fun testGenerated() {
+        C.serializer().descriptor.haveSealedSubclasses()
+    }
+
+    @Test
+    fun testResolved() {
+        serializer<C>().descriptor.haveSealedSubclasses()
+    }
+
+
+}