add test for a Java Record with an Optional param

src/test/java/tools/jackson/databind/records/RecordWithOptionalParamTest.java

@@ -0,0 +1,67 @@
+package tools.jackson.databind.records;
+
+import java.util.Optional;
+
+import org.junit.jupiter.api.Test;
+import tools.jackson.databind.ObjectMapper;
+import tools.jackson.databind.testutil.DatabindTestUtil;
+import tools.jackson.databind.testutil.failure.JacksonTestFailureExpected;
+
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+// [databind#5335] When deserializing records, java.util.Optional parameters should be not be
+// deserialized as null (Optional.empty() should be used instead)
+public class RecordWithOptionalParamTest
+    extends DatabindTestUtil
+{
+    record RecordWithOptionalParam(String name, Optional<String> optional) { }
+
+    private final ObjectMapper MAPPER = newJsonMapper();
+
+    @Test
+    void serialize() throws Exception
+    {
+        RecordWithOptionalParam input = new RecordWithOptionalParam("v1", Optional.of("v2"));
+        assertEquals(a2q("{'name':'v1','optional':'v2'}"),
+                MAPPER.writeValueAsString(input));
+    }
+
+    @Test
+    void serializeEmpty() throws Exception
+    {
+        RecordWithOptionalParam input = new RecordWithOptionalParam("v1", Optional.empty());
+        assertEquals(a2q("{'name':'v1','optional':null}"),
+                MAPPER.writeValueAsString(input));
+    }
+
+    @Test
+    void deserializeNonEmpty() throws Exception
+    {
+        String json = a2q("{'name':'v1','optional':'v2'}");
+        RecordWithOptionalParam output = MAPPER.readValue(json, RecordWithOptionalParam.class);
+        assertEquals("v1", output.name());
+        assertEquals(Optional.of("v2"), output.optional());
+    }
+
+    @Test
+    void deserializeExplicitNull() throws Exception
+    {
+        String json = a2q("{'name':'v1','optional':null}");
+        RecordWithOptionalParam output = MAPPER.readValue(json, RecordWithOptionalParam.class);
+        assertEquals("v1", output.name());
+        assertNotNull(output.optional());
+        assertEquals(Optional.empty(), output.optional());
+    }
+
+    @JacksonTestFailureExpected // [databind#5335]
+    @Test
+    void deserializeMissing() throws Exception
+    {
+        RecordWithOptionalParam output = MAPPER.readValue(a2q("{'name':'v1'}"),
+                RecordWithOptionalParam.class);
+        assertEquals("v1", output.name());
+        assertNotNull(output.optional());
+        assertEquals(Optional.empty(), output.optional());
+    }
+}