✅ add additional test coverage

src/main/kotlin/io/andrewohara/dynamokt/DataClassTableSchema.kt

@@ -3,17 +3,20 @@ package io.andrewohara.dynamokt
 import software.amazon.awssdk.enhanced.dynamodb.TableSchema
 import software.amazon.awssdk.enhanced.dynamodb.mapper.StaticImmutableTableSchema
 import kotlin.reflect.KClass
+import kotlin.reflect.KVisibility
 import kotlin.reflect.full.declaredMemberProperties
 import kotlin.reflect.full.primaryConstructor
 
 
 fun <Item: Any> DataClassTableSchema(dataClass: KClass<Item>): TableSchema<Item> {
     val props = dataClass.declaredMemberProperties.sortedBy { it.name }
     val params = dataClass.primaryConstructor!!.parameters.sortedBy { it.name }
+    val constructor = dataClass.primaryConstructor
+        ?.takeIf { it.visibility == KVisibility.PUBLIC }
+        ?: error("${dataClass.simpleName} must have a public primary constructor")
 
     require(dataClass.isData) { "$dataClass must be a data class" }
-    require(props.size == params.size) { "$dataClass properties MUST all be declared in the constructor" }
-    val constructor = requireNotNull(dataClass.primaryConstructor) { "$dataClass must have a primary constructor"}
+    require(props.size == params.size) { "${dataClass.simpleName} properties MUST all be declared in the constructor" }
 
     return StaticImmutableTableSchema.builder(dataClass.java, ImmutableDataClassBuilder::class.java)
         .newItemBuilder({ ImmutableDataClassBuilder(constructor) }, { it.build() as Item })

src/test/kotlin/io/andrewohara/dynamokt/DataClassTableSchemaTest.kt

@@ -7,6 +7,7 @@ import org.junit.jupiter.api.Test
 import software.amazon.awssdk.core.SdkBytes
 import software.amazon.awssdk.services.dynamodb.model.AttributeValue
 import java.lang.IllegalArgumentException
+import java.lang.IllegalStateException
 import java.nio.ByteBuffer
 
 class DataClassTableSchemaTest {
@@ -99,4 +100,20 @@ class DataClassTableSchemaTest {
             DataClassTableSchema(Person::class)
         }
     }
+
+    @Test
+    fun `non-data class throws error`() {
+        shouldThrow<IllegalArgumentException> {
+            DataClassTableSchema(String::class)
+        }.message shouldBe "class kotlin.String must be a data class"
+    }
+
+    @Test
+    fun `data class with private constructor`() {
+        data class Person private constructor(val name: String)
+
+        shouldThrow<IllegalStateException> {
+            DataClassTableSchema(Person::class)
+        }.message shouldBe "Person must have a public primary constructor"
+    }
 }