1 files changed, 25 insertions, 0 deletions
diff --git a/formats/json-tests/commonTest/src/kotlinx/serialization/json/polymorphic/JsonDeserializePolymorphicTwiceTest.kt b/formats/json-tests/commonTest/src/kotlinx/serialization/json/polymorphic/JsonDeserializePolymorphicTwiceTest.kt
new file mode 100644
index 00000000..f0229046
--- /dev/null
+++ b/formats/json-tests/commonTest/src/kotlinx/serialization/json/polymorphic/JsonDeserializePolymorphicTwiceTest.kt
@@ -0,0 +1,25 @@
+/*
+ * 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.Serializable
+import kotlinx.serialization.json.*
+import kotlin.test.*
+
+class JsonDeserializePolymorphicTwiceTest {
+
+    @Serializable
+    sealed class Foo {
+        @Serializable
+        data class Bar(val a: Int) : Foo()
+    }
+
+    @Test
+    fun testDeserializeTwice() { // #812
+        val json = Json.encodeToJsonElement(Foo.serializer(), Foo.Bar(1))
+        assertEquals(Foo.Bar(1), Json.decodeFromJsonElement(Foo.serializer(), json))
+        assertEquals(Foo.Bar(1), Json.decodeFromJsonElement(Foo.serializer(), json))
+    }
+}
+\ No newline at end of file