Document weird behavior wrt. to Enum Deserialisation

common/src/test/kotlin/de/sipgate/federmappe/common/decoder/ComplexEnumTests.kt

@@ -0,0 +1,78 @@
+package de.sipgate.federmappe.common.decoder
+
+import kotlinx.serialization.ExperimentalSerializationApi
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Serializable
+import kotlinx.serialization.SerializationException
+import kotlinx.serialization.serializer
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertFails
+import kotlin.test.assertIs
+
+/*
+ * This `@Serializable` annotation needs to be present for the `@SerialName` annotation to be
+ * processed and attached to the generated SerialDescriptor. This seems to be a side-effect of
+ * Kotlin JS deserialization. See https://github.com/Kotlin/kotlinx.serialization/issues/31#issuecomment-1446310243
+ * for details
+ */
+@Serializable
+enum class CustomTestEnum {
+    @SerialName("avalue") A,
+}
+
+private val expectedError = "Couldn't find matching de.sipgate.federmappe.common.decoder.CustomTestEnum enum for value A"
+
+@OptIn(ExperimentalSerializationApi::class)
+class ComplexEnumTests {
+    @Test
+    fun deserializeDataClassWithEnum() {
+        // Arrange
+        @Serializable
+        data class TestClassA(val a: CustomTestEnum)
+
+        val serializer = serializer<TestClassA>()
+        val data = mapOf<String, Any?>("a" to CustomTestEnum.A)
+
+        // Act
+        val result = assertFails { serializer.deserialize(StringMapToObjectDecoder(data)) }
+
+        // Assert
+        assertIs<SerializationException>(result)
+        assertEquals(expectedError, result.message)
+    }
+
+    @Test
+    fun deserializeDataClassWithEnumValue() {
+        // Arrange
+        @Serializable
+        data class TestClassA(val a: CustomTestEnum)
+
+        val serializer = serializer<TestClassA>()
+        val data = mapOf<String, Any?>("a" to "A")
+
+        // Act
+        val result = assertFails { serializer.deserialize(StringMapToObjectDecoder(data)) }
+
+        // Assert
+        assertIs<SerializationException>(result)
+        assertEquals(expectedError, result.message)
+    }
+
+    @Test
+    fun deserializeEnumWithCustomSerialName() {
+        // Arrange
+        @Serializable
+        data class TestClassA(val a: CustomTestEnum)
+
+        val serializer = serializer<TestClassA>()
+        val data = mapOf<String, Any?>("a" to "avalue")
+
+        // Act
+        val result = serializer.deserialize(StringMapToObjectDecoder(data))
+
+        // Assert
+        assertIs<TestClassA>(result)
+        assertEquals(CustomTestEnum.A, result.a)
+    }
+}