Merge pull request #430 from FasterXML/github-211-test

Add test case for GitHub #211

Author: dinomite

release-notes/CREDITS-2.x

@@ -13,6 +13,10 @@ Authors:
 
 Contributors:
 
+Jocelyn N'TAKPÉ (jntakpe@github)
+* #211: Contributed test case for @JsonMerge
+  (2.12.NEXT)
+
 Christopher Mason (masoncj@github)
 * #194: Contributed test case for @JsonIdentityInfo usage
   (2.12.NEXT)

src/test/kotlin/com/fasterxml/jackson/module/kotlin/test/github/Github211.kt

@@ -0,0 +1,47 @@
+package com.fasterxml.jackson.module.kotlin.test.github
+
+import com.fasterxml.jackson.annotation.JsonMerge
+import com.fasterxml.jackson.databind.JsonNode
+import com.fasterxml.jackson.databind.ObjectMapper
+import com.fasterxml.jackson.databind.node.JsonNodeFactory
+import com.fasterxml.jackson.databind.node.ObjectNode
+import com.fasterxml.jackson.module.kotlin.jacksonObjectMapper
+import org.junit.Test
+import kotlin.test.assertEquals
+
+class TestGithub211 {
+    @Test
+    fun simple() {
+        val original = Person("original", Address("Rivoli", "Paris"))
+        val changes = JsonNodeFactory.instance.objectNode().put("username", "updated")
+
+        val merged = JsonMerger(jacksonObjectMapper()).merge(original, changes)
+
+        assertEquals(original.copy(username = "updated"), merged)
+    }
+
+    @Test
+    fun nested() {
+        val original = Person("original", Address("Rivoli", "Paris"))
+
+        val merged = JsonMerger(jacksonObjectMapper()).merge(original, nestedChanges())
+
+        assertEquals(Person("updated", Address("Magenta", "Paris")), merged)
+    }
+
+    private fun nestedChanges(): ObjectNode {
+        return JsonNodeFactory.instance.objectNode().put("username", "updated").apply {
+            putObject("address").put("street", "Magenta")
+        }
+    }
+
+    class JsonMerger(private val objectMapper: ObjectMapper) {
+        fun <T> merge(toUpdate: T, changes: JsonNode): T {
+            return objectMapper.readerForUpdating(toUpdate).readValue(changes)
+        }
+    }
+
+    data class Address(val street: String, val city: String)
+
+    data class Person(val username: String, @JsonMerge val address: Address)
+}