Add kotlin/xml related test that breaks Jackson 2.12.0

See FasterXML/jackson-module-kotlin#396

pom.xml

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
-  <modelVersion>4.0.0</modelVersion> 
+  <modelVersion>4.0.0</modelVersion>
   <parent>
     <groupId>com.fasterxml.jackson</groupId>
     <artifactId>jackson-base</artifactId>
@@ -199,7 +199,7 @@
             <exclude>com/fasterxml/jackson/failing/*.java</exclude>
           </excludes>
         </configuration>
-      </plugin>    
+      </plugin>
       <plugin>
         <groupId>net.alchim31.maven</groupId>
         <artifactId>scala-maven-plugin</artifactId>
@@ -228,7 +228,9 @@
         <executions>
           <execution>
             <id>test-compile</id>
-            <goals> <goal>test-compile</goal> </goals>
+            <goals>
+              <goal>test-compile</goal>
+            </goals>
             <configuration>
               <sourceDirs>
                 <sourceDir>${project.basedir}/src/test/kotlin</sourceDir>

src/test/kotlin/com/fasterxml/jackson/integtest/kotlin/Jackson212MissingConstructorTest.kt

@@ -0,0 +1,27 @@
+import com.fasterxml.jackson.dataformat.xml.JacksonXmlModule
+import com.fasterxml.jackson.dataformat.xml.XmlFactory
+import com.fasterxml.jackson.dataformat.xml.XmlMapper
+import com.fasterxml.jackson.integtest.BaseTest
+import com.fasterxml.jackson.module.kotlin.registerKotlinModule
+import javax.xml.stream.XMLInputFactory
+
+class Jackson212MissingConstructorTest : BaseTest()
+{
+    /**
+     * Succeeds in Jackson 2.11.x, but fails in Jackson 2.12.0
+     * See https://github.com/FasterXML/jackson-module-kotlin/issues/396
+     */
+    fun testMissingConstructor()
+    {
+        val factory = XmlFactory(XMLInputFactory.newInstance())
+        val mapper = XmlMapper(factory, JacksonXmlModule()).registerKotlinModule()
+
+        val xml = "<product><stuff></stuff></product>"
+        val product: Product = mapper.readValue(xml, Product::class.java)
+
+        assertEquals(Product(null), product)
+    }
+
+    private data class Stuff(val str: String?)
+    private data class Product(val stuff: Stuff?)
+}