Make sure the type converters work with nulls

Author: jeffgbutler

src/test/kotlin/examples/kotlin/spring/canonical/CanonicalSpringKotlinTest.kt

@@ -925,4 +925,36 @@ class CanonicalSpringKotlinTest {
 
         assertThat(rows).isEqualTo(2)
     }
+
+    @Test
+    fun testUpdateWithTypeConverterAndNullValue() {
+        val record = PersonRecord(id = 3, firstName = "Sam")
+
+        val updateStatement = update(Person) {
+            set(firstName).equalTo(record::firstName)
+            set(lastName).equalTo(record::lastName)
+            where(id, isEqualTo(record::id))
+        }
+
+        assertThat(updateStatement.updateStatement).isEqualTo(
+            "update Person" +
+                    " set first_name = :p1," +
+                    " last_name = :p2" +
+                    " where id = :p3"
+        )
+
+        val rows = template.update(updateStatement)
+
+        assertThat(rows).isEqualTo(1)
+
+        val selectStatement = select(
+            id, firstName, lastName, birthDate, employed, occupation, addressId
+        ).from(Person) {
+            where(id, isEqualTo(record::id))
+        }
+
+        val returnedRecord = template.selectOne(selectStatement, ::personRowMapper)
+        assertThat(returnedRecord).isNotNull()
+        assertThat(returnedRecord!!.lastName).isNull()
+    }
 }

src/test/kotlin/examples/kotlin/spring/canonical/RowMappers.kt

@@ -17,11 +17,11 @@ package examples.kotlin.spring.canonical
 
 import java.sql.ResultSet
 
-fun personRowMapper(rs: ResultSet, rowNum : Int) =
+fun personRowMapper(rs: ResultSet, rowNum: Int) =
     PersonRecord().apply {
         id = rs.getInt(1)
         firstName = rs.getString(2)
-        lastName = LastName(rs.getString(3))
+        lastName = rs.getString(3)?.let { LastName(it) }
         birthDate = rs.getTimestamp(4)
         employed = "Yes" == rs.getString(5)
         occupation = rs.getString(6)
@@ -32,7 +32,7 @@ fun personWithAddressRowMapper(rs: ResultSet, rowNum: Int) =
     PersonWithAddress().apply {
         id = rs.getInt(1)
         firstName = rs.getString(2)
-        lastName = LastName(rs.getString(3))
+        lastName = rs.getString(3)?.let { LastName(it) }
         birthDate = rs.getTimestamp(4)
         employed = "Yes" == rs.getString(5)
         occupation = rs.getString(6)

src/test/resources/examples/kotlin/spring/CreateSimpleDB.sql

@@ -28,7 +28,7 @@ create table Address (
 create table Person (
    id int not null,
    first_name varchar(30) not null,
-   last_name varchar(30) not null,
+   last_name varchar(30) null,
    birth_date date not null,
    employed varchar(3) not null,
    occupation varchar(30) null,