1 files changed, 103 insertions, 0 deletions
diff --git a/formats/json-tests/commonTest/src/kotlinx/serialization/json/polymorphic/JsonContentPolymorphicSerializerTest.kt b/formats/json-tests/commonTest/src/kotlinx/serialization/json/polymorphic/JsonContentPolymorphicSerializerTest.kt
new file mode 100644
index 00000000..d58e26b6
--- /dev/null
+++ b/formats/json-tests/commonTest/src/kotlinx/serialization/json/polymorphic/JsonContentPolymorphicSerializerTest.kt
@@ -0,0 +1,103 @@
+/*
+ * Copyright 2017-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
+ */
+
+package kotlinx.serialization.json.polymorphic
+
+import kotlinx.serialization.*
+import kotlinx.serialization.json.*
+import kotlin.test.*
+
+class JsonContentPolymorphicSerializerTest : JsonTestBase() {
+    val json = Json
+
+    @Serializable
+    sealed class Choices {
+        @Serializable
+        data class HasA(val a: String) : Choices()
+
+        @Serializable
+        data class HasB(val b: Int) : Choices()
+
+        @Serializable
+        data class HasC(val c: Boolean) : Choices()
+    }
+
+    object ChoicesParametricSerializer : JsonContentPolymorphicSerializer<Choices>(Choices::class) {
+        override fun selectDeserializer(element: JsonElement): KSerializer<out Choices> {
+            val obj = element.jsonObject
+            return when {
+                "a" in obj -> Choices.HasA.serializer()
+                "b" in obj -> Choices.HasB.serializer()
+                "c" in obj -> Choices.HasC.serializer()
+                else -> throw SerializationException("Unknown choice")
+            }
+        }
+    }
+
+    @Serializable
+    data class WithChoices(@Serializable(ChoicesParametricSerializer::class) val response: Choices)
+
+    private val testDataInput = listOf(
+        """{"response":{"a":"string"}}""",
+        """{"response":{"b":42}}""",
+        """{"response":{"c":true}}"""
+    )
+
+    private val testDataOutput = listOf(
+        WithChoices(Choices.HasA("string")),
+        WithChoices(Choices.HasB(42)),
+        WithChoices(Choices.HasC(true))
+    )
+
+    @Test
+    fun testParsesParametrically() = parametrizedTest { streaming ->
+        for (i in testDataInput.indices) {
+            assertEquals(
+                testDataOutput[i],
+                json.decodeFromString(WithChoices.serializer(), testDataInput[i], streaming),
+                "failed test on ${testDataInput[i]}, jsonTestingMode = $streaming"
+            )
+        }
+    }
+
+    @Test
+    fun testSerializesParametrically() = parametrizedTest { streaming ->
+        for (i in testDataOutput.indices) {
+            assertEquals(
+                testDataInput[i],
+                json.encodeToString(WithChoices.serializer(), testDataOutput[i], streaming),
+                "failed test on ${testDataOutput[i]}, jsonTestingMode = $streaming"
+            )
+        }
+    }
+
+    interface Payment {
+        val amount: String
+    }
+
+    @Serializable
+    data class SuccessfulPayment(override val amount: String, val date: String) : Payment
+
+    @Serializable
+    data class RefundedPayment(override val amount: String, val date: String, val reason: String) : Payment
+
+    object PaymentSerializer : JsonContentPolymorphicSerializer<Payment>(Payment::class) {
+        override fun selectDeserializer(element: JsonElement) = when {
+            "reason" in element.jsonObject -> RefundedPayment.serializer()
+            else -> SuccessfulPayment.serializer()
+        }
+    }
+
+    @Test
+    fun testDocumentationSample() = parametrizedTest { streaming ->
+        assertEquals(
+            SuccessfulPayment("1.0", "03.02.2020"),
+            json.decodeFromString(PaymentSerializer, """{"amount":"1.0","date":"03.02.2020"}""", streaming)
+        )
+        assertEquals(
+            RefundedPayment("2.0", "03.02.2020", "complaint"),
+            json.decodeFromString(PaymentSerializer, """{"amount":"2.0","date":"03.02.2020","reason":"complaint"}""", streaming)
+        )
+    }
+}