diff --git a/src/test/kotlin/com/fasterxml/jackson/module/kotlin/kogeraIntegration/ser.valueClass/JsonKeyTest.kt b/src/test/kotlin/com/fasterxml/jackson/module/kotlin/kogeraIntegration/ser.valueClass/JsonKeyTest.kt
new file mode 100644
index 000000000..55ce3025e
--- /dev/null
+++ b/src/test/kotlin/com/fasterxml/jackson/module/kotlin/kogeraIntegration/ser.valueClass/JsonKeyTest.kt
@@ -0,0 +1,54 @@
+package com.fasterxml.jackson.module.kotlin.kogeraIntegration.ser.valueClass
+
+import com.fasterxml.jackson.annotation.JsonKey
+import com.fasterxml.jackson.module.kotlin.jacksonMapperBuilder
+import com.fasterxml.jackson.module.kotlin.testPrettyWriter
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+class JsonKeyTest {
+    @JvmInline
+    value class JsonKeyGetter(val value: Int) {
+        @get:JsonKey
+        val jsonKey: String
+            get() = this.toString()
+    }
+
+    interface IJsonKeyGetter {
+        @get:JsonKey
+        val jsonKey: String
+            get() = this.toString()
+    }
+
+    @JvmInline
+    value class JsonKeyGetterImplementation(val value: Int) : IJsonKeyGetter
+
+    @JvmInline
+    value class JsonKeyGetterImplementationDisabled(val value: Int) : IJsonKeyGetter {
+        @get:JsonKey(false)
+        override val jsonKey: String
+            get() = super.jsonKey
+    }
+
+    private val writer = jacksonMapperBuilder().build().testPrettyWriter()
+
+    @Test
+    fun test() {
+        val src = mapOf(
+            JsonKeyGetter(0) to 0,
+            JsonKeyGetterImplementation(1) to 1,
+            JsonKeyGetterImplementationDisabled(2) to 2
+        )
+
+        assertEquals(
+            """
+                {
+                  "JsonKeyGetter(value=0)" : 0,
+                  "JsonKeyGetterImplementation(value=1)" : 1,
+                  "2" : 2
+                }
+            """.trimIndent(),
+            writer.writeValueAsString(src)
+        )
+    }
+}
diff --git a/src/test/kotlin/com/fasterxml/jackson/module/kotlin/kogeraIntegration/ser.valueClass/jsonInclude/JsonIncludeCustomTest.kt b/src/test/kotlin/com/fasterxml/jackson/module/kotlin/kogeraIntegration/ser.valueClass/jsonInclude/JsonIncludeCustomTest.kt
new file mode 100644
index 000000000..a162e482f
--- /dev/null
+++ b/src/test/kotlin/com/fasterxml/jackson/module/kotlin/kogeraIntegration/ser.valueClass/jsonInclude/JsonIncludeCustomTest.kt
@@ -0,0 +1,29 @@
+package com.fasterxml.jackson.module.kotlin.kogeraIntegration.ser.valueClass.jsonInclude
+
+import com.fasterxml.jackson.annotation.JsonInclude
+import com.fasterxml.jackson.module.kotlin.jacksonObjectMapper
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+class JsonIncludeCustomTest {
+    class NullFilter {
+        override fun equals(other: Any?) = other == null
+    }
+
+    @JsonInclude(
+        value = JsonInclude.Include.CUSTOM,
+        valueFilter = NullFilter::class
+    )
+    data class NullFilterDto(
+        val pN: Primitive? = null,
+        val nnoN: NonNullObject? = null,
+        val noN1: NullableObject? = null
+    )
+
+    @Test
+    fun nullFilterTest() {
+        val mapper = jacksonObjectMapper()
+        val dto = NullFilterDto()
+        assertEquals("{}", mapper.writeValueAsString(dto))
+    }
+}
diff --git a/src/test/kotlin/com/fasterxml/jackson/module/kotlin/kogeraIntegration/ser.valueClass/jsonInclude/JsonIncludeNonNullTest.kt b/src/test/kotlin/com/fasterxml/jackson/module/kotlin/kogeraIntegration/ser.valueClass/jsonInclude/JsonIncludeNonNullTest.kt
new file mode 100644
index 000000000..82de3fe62
--- /dev/null
+++ b/src/test/kotlin/com/fasterxml/jackson/module/kotlin/kogeraIntegration/ser.valueClass/jsonInclude/JsonIncludeNonNullTest.kt
@@ -0,0 +1,41 @@
+package com.fasterxml.jackson.module.kotlin.kogeraIntegration.ser.valueClass.jsonInclude
+
+import com.fasterxml.jackson.annotation.JsonInclude
+import com.fasterxml.jackson.module.kotlin.jacksonObjectMapper
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertNotEquals
+
+class JsonIncludeNonNullTest {
+    @JsonInclude(value = JsonInclude.Include.NON_NULL)
+    data class Dto(
+        val pN: Primitive? = null,
+        val nnoN: NonNullObject? = null,
+        val noN1: NullableObject? = null
+    )
+
+    @Test
+    fun success() {
+        val mapper = jacksonObjectMapper()
+        val dto = Dto()
+        assertEquals("{}", mapper.writeValueAsString(dto))
+    }
+
+    // It is under consideration whether it should be serialized because it is non-null in Kotlin,
+    // but it is tentatively regarded as a failure.
+    @JsonInclude(value = JsonInclude.Include.NON_NULL, content = JsonInclude.Include.NON_NULL)
+    data class DtoFails(
+        val noNn: NullableObject = NullableObject(null),
+        val noN2: NullableObject? = NullableObject(null),
+        val map: Map<Any, Any?> = mapOf("noNn" to NullableObject(null))
+    )
+
+    @Test
+    fun fails() {
+        val mapper = jacksonObjectMapper()
+        val dto = DtoFails()
+        val result = mapper.writeValueAsString(dto)
+        assertNotEquals("""{"map":{}}""", result)
+        assertEquals("""{"noNn":null,"noN2":null,"map":{"noNn":null}}""", result)
+    }
+}
diff --git a/src/test/kotlin/com/fasterxml/jackson/module/kotlin/kogeraIntegration/ser.valueClass/jsonInclude/ValueClasses.kt b/src/test/kotlin/com/fasterxml/jackson/module/kotlin/kogeraIntegration/ser.valueClass/jsonInclude/ValueClasses.kt
new file mode 100644
index 000000000..1a6804cd4
--- /dev/null
+++ b/src/test/kotlin/com/fasterxml/jackson/module/kotlin/kogeraIntegration/ser.valueClass/jsonInclude/ValueClasses.kt
@@ -0,0 +1,10 @@
+package com.fasterxml.jackson.module.kotlin.kogeraIntegration.ser.valueClass.jsonInclude
+
+@JvmInline
+value class Primitive(val v: Int)
+
+@JvmInline
+value class NonNullObject(val v: String)
+
+@JvmInline
+value class NullableObject(val v: String?)
diff --git a/src/test/kotlin/com/fasterxml/jackson/module/kotlin/kogeraIntegration/ser.valueClass/serializer/ValueClasses.kt b/src/test/kotlin/com/fasterxml/jackson/module/kotlin/kogeraIntegration/ser.valueClass/serializer/ValueClasses.kt
new file mode 100644
index 000000000..30ef5ddd8
--- /dev/null
+++ b/src/test/kotlin/com/fasterxml/jackson/module/kotlin/kogeraIntegration/ser.valueClass/serializer/ValueClasses.kt
@@ -0,0 +1,32 @@
+package com.fasterxml.jackson.module.kotlin.kogeraIntegration.ser.valueClass.serializer
+
+import com.fasterxml.jackson.core.JsonGenerator
+import com.fasterxml.jackson.databind.SerializerProvider
+import com.fasterxml.jackson.databind.ser.std.StdSerializer
+
+@JvmInline
+value class Primitive(val v: Int) {
+    class Serializer : StdSerializer<Primitive>(Primitive::class.java) {
+        override fun serialize(value: Primitive, gen: JsonGenerator, provider: SerializerProvider) {
+            gen.writeNumber(value.v + 100)
+        }
+    }
+}
+
+@JvmInline
+value class NonNullObject(val v: String) {
+    class Serializer : StdSerializer<NonNullObject>(NonNullObject::class.java) {
+        override fun serialize(value: NonNullObject, gen: JsonGenerator, provider: SerializerProvider) {
+            gen.writeString("${value.v}-ser")
+        }
+    }
+}
+
+@JvmInline
+value class NullableObject(val v: String?) {
+    class Serializer : StdSerializer<NullableObject>(NullableObject::class.java) {
+        override fun serialize(value: NullableObject, gen: JsonGenerator, provider: SerializerProvider) {
+            gen.writeString(value.v?.let { "$it-ser" } ?: "NULL")
+        }
+    }
+}
diff --git a/src/test/kotlin/com/fasterxml/jackson/module/kotlin/kogeraIntegration/ser.valueClass/serializer/byAnnotation/nonNullObject/ByAnnotationTest.kt b/src/test/kotlin/com/fasterxml/jackson/module/kotlin/kogeraIntegration/ser.valueClass/serializer/byAnnotation/nonNullObject/ByAnnotationTest.kt
new file mode 100644
index 000000000..648cdeb22
--- /dev/null
+++ b/src/test/kotlin/com/fasterxml/jackson/module/kotlin/kogeraIntegration/ser.valueClass/serializer/byAnnotation/nonNullObject/ByAnnotationTest.kt
@@ -0,0 +1,73 @@
+package com.fasterxml.jackson.module.kotlin.kogeraIntegration.ser.valueClass.serializer.byAnnotation.nonNullObject
+
+import com.fasterxml.jackson.databind.annotation.JsonSerialize
+import com.fasterxml.jackson.module.kotlin.jacksonObjectMapper
+import com.fasterxml.jackson.module.kotlin.testPrettyWriter
+import com.fasterxml.jackson.module.kotlin.kogeraIntegration.ser.valueClass.serializer.NonNullObject
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+class ByAnnotationTest {
+    companion object {
+        val writer = jacksonObjectMapper().testPrettyWriter()
+    }
+
+    data class NonNullSrc(
+        @get:JsonSerialize(using = NonNullObject.Serializer::class)
+        val getterAnn: NonNullObject,
+        @field:JsonSerialize(using = NonNullObject.Serializer::class)
+        val fieldAnn: NonNullObject
+    )
+
+    @Test
+    fun nonNull() {
+        val src = NonNullSrc(NonNullObject("foo"), NonNullObject("bar"))
+
+        assertEquals(
+            """
+                {
+                  "getterAnn" : "foo-ser",
+                  "fieldAnn" : "bar-ser"
+                }
+            """.trimIndent(),
+            writer.writeValueAsString(src)
+        )
+    }
+
+    data class NullableSrc(
+        @get:JsonSerialize(using = NonNullObject.Serializer::class)
+        val getterAnn: NonNullObject?,
+        @field:JsonSerialize(using = NonNullObject.Serializer::class)
+        val fieldAnn: NonNullObject?
+    )
+
+    @Test
+    fun nullableWithoutNull() {
+        val src = NullableSrc(NonNullObject("foo"), NonNullObject("bar"))
+
+        assertEquals(
+            """
+                {
+                  "getterAnn" : "foo-ser",
+                  "fieldAnn" : "bar-ser"
+                }
+            """.trimIndent(),
+            writer.writeValueAsString(src)
+        )
+    }
+
+    @Test
+    fun nullableWithNull() {
+        val src = NullableSrc(null, null)
+
+        assertEquals(
+            """
+                {
+                  "getterAnn" : null,
+                  "fieldAnn" : null
+                }
+            """.trimIndent(),
+            writer.writeValueAsString(src)
+        )
+    }
+}
diff --git a/src/test/kotlin/com/fasterxml/jackson/module/kotlin/kogeraIntegration/ser.valueClass/serializer/byAnnotation/nullableObject/byAnnotation/NonNullValueTest.kt b/src/test/kotlin/com/fasterxml/jackson/module/kotlin/kogeraIntegration/ser.valueClass/serializer/byAnnotation/nullableObject/byAnnotation/NonNullValueTest.kt
new file mode 100644
index 000000000..caaa60465
--- /dev/null
+++ b/src/test/kotlin/com/fasterxml/jackson/module/kotlin/kogeraIntegration/ser.valueClass/serializer/byAnnotation/nullableObject/byAnnotation/NonNullValueTest.kt
@@ -0,0 +1,73 @@
+package com.fasterxml.jackson.module.kotlin.kogeraIntegration.ser.valueClass.serializer.byAnnotation.nullableObject.byAnnotation
+
+import com.fasterxml.jackson.databind.annotation.JsonSerialize
+import com.fasterxml.jackson.module.kotlin.jacksonObjectMapper
+import com.fasterxml.jackson.module.kotlin.testPrettyWriter
+import com.fasterxml.jackson.module.kotlin.kogeraIntegration.ser.valueClass.serializer.NullableObject
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+class NonNullValueTest {
+    companion object {
+        val writer = jacksonObjectMapper().testPrettyWriter()
+    }
+
+    data class NonNullSrc(
+        @get:JsonSerialize(using = NullableObject.Serializer::class)
+        val getterAnn: NullableObject,
+        @field:JsonSerialize(using = NullableObject.Serializer::class)
+        val fieldAnn: NullableObject
+    )
+
+    @Test
+    fun nonNull() {
+        val src = NonNullSrc(NullableObject("foo"), NullableObject("bar"))
+
+        assertEquals(
+            """
+                {
+                  "getterAnn" : "foo-ser",
+                  "fieldAnn" : "bar-ser"
+                }
+            """.trimIndent(),
+            writer.writeValueAsString(src)
+        )
+    }
+
+    data class NullableSrc(
+        @get:JsonSerialize(using = NullableObject.Serializer::class)
+        val getterAnn: NullableObject?,
+        @field:JsonSerialize(using = NullableObject.Serializer::class)
+        val fieldAnn: NullableObject?
+    )
+
+    @Test
+    fun nullableWithoutNull() {
+        val src = NullableSrc(NullableObject("foo"), NullableObject("bar"))
+
+        assertEquals(
+            """
+                {
+                  "getterAnn" : "foo-ser",
+                  "fieldAnn" : "bar-ser"
+                }
+            """.trimIndent(),
+            writer.writeValueAsString(src)
+        )
+    }
+
+    @Test
+    fun nullableWithNull() {
+        val src = NullableSrc(null, null)
+
+        assertEquals(
+            """
+                {
+                  "getterAnn" : null,
+                  "fieldAnn" : null
+                }
+            """.trimIndent(),
+            writer.writeValueAsString(src)
+        )
+    }
+}
diff --git a/src/test/kotlin/com/fasterxml/jackson/module/kotlin/kogeraIntegration/ser.valueClass/serializer/byAnnotation/nullableObject/byAnnotation/NullValueTest.kt b/src/test/kotlin/com/fasterxml/jackson/module/kotlin/kogeraIntegration/ser.valueClass/serializer/byAnnotation/nullableObject/byAnnotation/NullValueTest.kt
new file mode 100644
index 000000000..61f4c1232
--- /dev/null
+++ b/src/test/kotlin/com/fasterxml/jackson/module/kotlin/kogeraIntegration/ser.valueClass/serializer/byAnnotation/nullableObject/byAnnotation/NullValueTest.kt
@@ -0,0 +1,74 @@
+package com.fasterxml.jackson.module.kotlin.kogeraIntegration.ser.valueClass.serializer.byAnnotation.nullableObject.byAnnotation
+
+import com.fasterxml.jackson.databind.annotation.JsonSerialize
+import com.fasterxml.jackson.module.kotlin.jacksonObjectMapper
+import com.fasterxml.jackson.module.kotlin.testPrettyWriter
+import com.fasterxml.jackson.module.kotlin.kogeraIntegration.ser.valueClass.serializer.NullableObject
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertNotEquals
+
+class NullValueTest {
+    companion object {
+        val writer = jacksonObjectMapper().testPrettyWriter()
+    }
+
+    data class NonNullSrc(
+        @get:JsonSerialize(using = NullableObject.Serializer::class)
+        val getterAnn: NullableObject,
+        @field:JsonSerialize(using = NullableObject.Serializer::class)
+        val fieldAnn: NullableObject
+    )
+
+    @Test
+    fun failing() {
+        val src = NonNullSrc(NullableObject(null), NullableObject(null))
+
+        assertNotEquals(
+            """
+                {
+                  "getterAnn" : "NULL",
+                  "fieldAnn" : "NULL"
+                }
+            """.trimIndent(),
+            writer.writeValueAsString(src)
+        )
+    }
+
+    data class NullableSrc(
+        @get:JsonSerialize(using = NullableObject.Serializer::class)
+        val getterAnn: NullableObject?,
+        @field:JsonSerialize(using = NullableObject.Serializer::class)
+        val fieldAnn: NullableObject?
+    )
+
+    @Test
+    fun nullableWithoutNull() {
+        val src = NullableSrc(NullableObject(null), NullableObject(null))
+
+        assertEquals(
+            """
+                {
+                  "getterAnn" : "NULL",
+                  "fieldAnn" : "NULL"
+                }
+            """.trimIndent(),
+            writer.writeValueAsString(src)
+        )
+    }
+
+    @Test
+    fun nullableWithNull() {
+        val src = NullableSrc(null, null)
+
+        assertEquals(
+            """
+                {
+                  "getterAnn" : null,
+                  "fieldAnn" : null
+                }
+            """.trimIndent(),
+            writer.writeValueAsString(src)
+        )
+    }
+}
diff --git a/src/test/kotlin/com/fasterxml/jackson/module/kotlin/kogeraIntegration/ser.valueClass/serializer/byAnnotation/primitive/ByAnnotationTest.kt b/src/test/kotlin/com/fasterxml/jackson/module/kotlin/kogeraIntegration/ser.valueClass/serializer/byAnnotation/primitive/ByAnnotationTest.kt
new file mode 100644
index 000000000..bac4c6b0f
--- /dev/null
+++ b/src/test/kotlin/com/fasterxml/jackson/module/kotlin/kogeraIntegration/ser.valueClass/serializer/byAnnotation/primitive/ByAnnotationTest.kt
@@ -0,0 +1,119 @@
+package com.fasterxml.jackson.module.kotlin.kogeraIntegration.ser.valueClass.serializer.byAnnotation.primitive
+
+import com.fasterxml.jackson.databind.ObjectMapper
+import com.fasterxml.jackson.databind.annotation.JsonSerialize
+import com.fasterxml.jackson.module.kotlin.KotlinModule
+import com.fasterxml.jackson.module.kotlin.testPrettyWriter
+import com.fasterxml.jackson.module.kotlin.kogeraIntegration.ser.valueClass.serializer.Primitive
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertNotEquals
+
+class ByAnnotationTest {
+    companion object {
+        val writer = KotlinModule.Builder()
+            .build()
+            .let { ObjectMapper().registerModule(it) }
+            .testPrettyWriter()
+    }
+
+    data class NonNullFailingSrc(
+        @JsonSerialize(using = Primitive.Serializer::class)
+        val paramAnn: Primitive,
+    )
+
+    @Test
+    fun nonNullFailing() {
+        val src = NullableFailingSrc(Primitive(0))
+
+        assertNotEquals(
+            """
+                {
+                  "paramAnn" : 100
+                }
+            """.trimIndent(),
+            writer.writeValueAsString(src),
+            "#651 fixed, it needs to be modified to match the original."
+        )
+    }
+
+    data class NonNullSrc(
+        @get:JsonSerialize(using = Primitive.Serializer::class)
+        val getterAnn: Primitive,
+        @field:JsonSerialize(using = Primitive.Serializer::class)
+        val fieldAnn: Primitive
+    )
+
+    @Test
+    fun nonNull() {
+        val src = NonNullSrc(Primitive(1), Primitive(2))
+
+        assertEquals(
+            """
+                {
+                  "getterAnn" : 101,
+                  "fieldAnn" : 102
+                }
+            """.trimIndent(),
+            writer.writeValueAsString(src)
+        )
+    }
+
+    data class NullableFailingSrc(
+        @JsonSerialize(using = Primitive.Serializer::class)
+        val paramAnn: Primitive?,
+    )
+
+    @Test
+    fun nullableFailing() {
+        val src = NullableFailingSrc(Primitive(0))
+
+        assertNotEquals(
+            """
+                {
+                  "paramAnn" : 100
+                }
+            """.trimIndent(),
+            writer.writeValueAsString(src),
+            "#651 fixed, it needs to be modified to match the original."
+        )
+    }
+
+
+    data class NullableSrc(
+        @get:JsonSerialize(using = Primitive.Serializer::class)
+        val getterAnn: Primitive?,
+        @field:JsonSerialize(using = Primitive.Serializer::class)
+        val fieldAnn: Primitive?
+    )
+
+    @Test
+    fun nullableWithoutNull() {
+        val src = NullableSrc(Primitive(1), Primitive(2))
+
+        assertEquals(
+            """
+                {
+                  "getterAnn" : 101,
+                  "fieldAnn" : 102
+                }
+            """.trimIndent(),
+            writer.writeValueAsString(src)
+        )
+    }
+
+    @Test
+    fun nullableWithNull() {
+        val src = NullableSrc(null, null)
+
+        assertEquals(
+            """
+                {
+                  "getterAnn" : null,
+                  "fieldAnn" : null
+                }
+            """.trimIndent(),
+            writer.writeValueAsString(src)
+        )
+    }
+}