Fix generating Kotlin sealed object type definition (#1163)

Author: seongahjo

fixture-monkey-kotlin/src/main/kotlin/com/navercorp/fixturemonkey/kotlin/KotlinPlugin.kt

@@ -85,7 +85,6 @@ class KotlinPlugin : Plugin {
                     CandidateConcretePropertyResolver { property ->
                         ConcreteTypeCandidateConcretePropertyResolver(
                             property.type.actualType().cachedKotlin().sealedSubclasses
-                                .filter { it.objectInstance == null }
                                 .map { it.java }
                         )
                             .resolve(property)

fixture-monkey-tests/kotlin-tests/src/test/kotlin/com/navercorp/fixturemonkey/tests/kotlin/SealedClassTest.kt

@@ -23,6 +23,7 @@ import com.navercorp.fixturemonkey.kotlin.KotlinPlugin
 import com.navercorp.fixturemonkey.kotlin.giveMeBuilder
 import com.navercorp.fixturemonkey.kotlin.giveMeOne
 import com.navercorp.fixturemonkey.tests.TestEnvironment.TEST_COUNT
+import com.navercorp.fixturemonkey.tests.kotlin.SealedClassTest.SealedObjectClass.ConcreteSealedObjectClass
 import org.assertj.core.api.BDDAssertions.then
 import org.junit.jupiter.api.RepeatedTest
 
@@ -71,24 +72,22 @@ class SealedClassTest {
 
     @RepeatedTest(TEST_COUNT)
     fun sealedObject() {
-        val actual: ObjectSealedClass = SUT.giveMeOne()
+        val actual: SealedObjectClass = SUT.giveMeOne()
 
-        then(actual).isInstanceOf(ObjectSealedClass::class.java)
+        then(actual).isInstanceOf(ConcreteSealedObjectClass::class.java)
     }
 
     @RepeatedTest(TEST_COUNT)
     fun sealedObjectThenApply() {
-        val actual = SUT.giveMeBuilder<ObjectSealedClass>()
-            .thenApply { obj, builder ->  }
+        val actual = SUT.giveMeBuilder<SealedObjectClass>()
+            .thenApply { obj, builder -> }
             .sample()
 
-        then(actual).isInstanceOf(ObjectSealedClass::class.java)
+        then(actual).isInstanceOf(ConcreteSealedObjectClass::class.java)
     }
 
     sealed class SealedClass
 
-    object ObjectSealedClass : SealedClass()
-
     class ImplementedSealedClass(
         val string: String,
         val integer: Int,
@@ -110,6 +109,10 @@ class SealedClassTest {
 
     class StringObject(val string: String)
 
+    sealed class SealedObjectClass {
+        object ConcreteSealedObjectClass : SealedObjectClass()
+    }
+
     companion object {
         val SUT: FixtureMonkey = FixtureMonkey.builder()
             .plugin(KotlinPlugin())