Add test for #873

src/test/kotlin/com/fasterxml/jackson/module/kotlin/test/github/GitHub873.kt

@@ -0,0 +1,45 @@
+package com.fasterxml.jackson.module.kotlin.test.github
+
+import com.fasterxml.jackson.module.kotlin.jacksonObjectMapper
+import com.fasterxml.jackson.module.kotlin.readValue
+import kotlin.test.Test
+
+class GitHub873 {
+    @Test
+    fun `should serialize value class`() {
+
+        val person = Person(
+            mapOf(
+                "id" to "123",
+                "updated" to "2023-11-22 12:11:23",
+                "login" to "2024-01-15",
+            ),
+        )
+
+        val serialized = jacksonObjectMapper().writeValueAsString(
+            TimestampedPerson(
+                123L,
+                Person(person.properties),
+            )
+        )
+
+        val deserialized = jacksonObjectMapper().readValue<TimestampedPerson>(serialized)
+
+        assert(
+            deserialized == TimestampedPerson(
+                123L,
+                Person(person.properties),
+            )
+        )
+    }
+
+    @JvmInline
+    value class Person(
+        val properties: Map<String, Any>,
+    )
+
+    data class TimestampedPerson(
+        val timestamp: Long,
+        val person: Person,
+    )
+}