test for issue 2422

src/test/scala/com/fasterxml/jackson/module/scala/deser/ListMapTest.scala

@@ -0,0 +1,74 @@
+package com.fasterxml.jackson.module.scala.deser
+
+import java.io.StringWriter
+
+import com.fasterxml.jackson.databind.{DeserializationFeature, MapperFeature, ObjectMapper, SerializationFeature}
+import com.fasterxml.jackson.module.scala.DefaultScalaModule
+import org.junit.runner.RunWith
+import org.scalatest.{FlatSpec, Matchers}
+import org.scalatest.prop.TableDrivenPropertyChecks
+import org.scalatestplus.junit.JUnitRunner
+
+import scala.collection.immutable.{ListMap, Queue, Stack, TreeMap}
+
+// taken from https://github.com/dejanlokar1/serialization_problem/blob/master/src/test/scala/SerializationTest.scala
+// test for https://github.com/FasterXML/jackson-databind/issues/2422
+
+@RunWith(classOf[JUnitRunner])
+class ListMapTest extends FlatSpec with Matchers with TableDrivenPropertyChecks {
+  private val mapper = {
+    val _mapper = new ObjectMapper
+    _mapper.registerModule(DefaultScalaModule)
+    _mapper.disable(MapperFeature.AUTO_DETECT_IS_GETTERS)
+    _mapper.disable(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES)
+    _mapper.disable(SerializationFeature.INDENT_OUTPUT)
+    _mapper
+  }
+
+  case class SampleCaseClass(map: Map[String, String] = Map(), seq: Seq[String] = List())
+
+  "Map Serialization" should "handle problematic list map" ignore {
+    val sampleListMap = ListMap("foo" -> "bar")
+    val sampleCaseClass = SampleCaseClass(map = sampleListMap)
+
+    // list map can be serialized
+    serialize(sampleListMap) shouldBe """{"foo":"bar"}"""
+    // list map in a case class can not be serialized
+    serialize(sampleCaseClass) shouldBe """{"map":{"foo":"bar"},"seq":[]}"""
+  }
+
+  "Map Serialization" should "handle working maps" in {
+    val maps = Table(
+      "Map implementations",
+      Map("foo" -> "bar"),
+      TreeMap("foo" -> "bar")
+    )
+
+    forAll(maps) { map =>
+      val sampleCaseClass = SampleCaseClass(map = map)
+      serialize(sampleCaseClass) shouldBe """{"map":{"foo":"bar"},"seq":[]}"""
+    }
+  }
+
+  "Map Serialization" should "handle working sequences" in {
+    val sequences = Table(
+      "Sequence implementations",
+      List("foo"),
+      Stack("foo"),
+      Stream("foo"),
+      Queue("foo"),
+      Vector("foo")
+    )
+
+    forAll(sequences) { seq =>
+      val sampleCaseClass = SampleCaseClass(seq = seq)
+      serialize(sampleCaseClass) shouldBe """{"map":{},"seq":["foo"]}"""
+    }
+  }
+
+  private def serialize(value: Any): String = {
+    val writer = new StringWriter()
+    mapper.writeValue(writer, value)
+    writer.toString
+  }
+}