diff --git a/2021/src/test/kotlin/BaseDayTest.kt b/2021/src/test/kotlin/BaseDayTest.kt
index 9d22acd..811510b 100644
--- a/2021/src/test/kotlin/BaseDayTest.kt
+++ b/2021/src/test/kotlin/BaseDayTest.kt
@@ -7,17 +7,40 @@ import org.assertj.core.api.Assertions
 import org.junit.jupiter.api.AfterAll
 import org.junit.jupiter.api.Test
 import org.junit.jupiter.api.TestInstance
+import org.junit.jupiter.api.extension.ConditionEvaluationResult
+import org.junit.jupiter.api.extension.ExecutionCondition
+import org.junit.jupiter.api.extension.ExtendWith
+import org.junit.jupiter.api.extension.ExtensionContext
+
+class Condition : ExecutionCondition {
+    private val methods: Map<String, (BaseDayTest) -> Any?> = mapOf(
+        "part1 example result" to { it.part1Example },
+        "part1 result" to { it.part1Answer },
+        "part2 example result" to { it.part2Example },
+        "part2 result" to { it.part2Answer },
+    )
+
+    override fun evaluateExecutionCondition(context: ExtensionContext): ConditionEvaluationResult {
+        val methodName = context.testMethod.orElseGet { null }?.name
+        methods[methodName]?.let {
+            val instance = context.testInstance.get() as BaseDayTest
+            if (it(instance) == null) return ConditionEvaluationResult.disabled("")
+        }
+        return ConditionEvaluationResult.enabled("")
+    }
+}
 
 @TestInstance(TestInstance.Lifecycle.PER_CLASS)
+@ExtendWith(Condition::class)
 abstract class BaseDayTest(day: Int) {
 
     abstract val example: String
 
-    abstract val part1Example: Any
-    abstract val part2Example: Any
+    abstract val part1Example: Any?
+    abstract val part1Answer: Any?
 
-    abstract val part1Answer: Any
-    abstract val part2Answer: Any
+    abstract val part2Example: Any?
+    abstract val part2Answer: Any?
 
     private val ctx = lazy {
         BeanContext.run()
@@ -25,7 +48,6 @@ abstract class BaseDayTest(day: Int) {
 
     val instance by lazy { ctx.value.getBean(ctx.value.findDayDefinition(day)) }
 
-
     private val exampleCtx = lazy {
         BeanContext.build()
             .apply { registerExampleLoader(example) }
@@ -39,9 +61,6 @@ abstract class BaseDayTest(day: Int) {
         arrayOf(ctx, exampleCtx).filter { it.isInitialized() }.forEach { it.value.stop() }
     }
 
-    private fun BeanContext.run(instance: Any, method: String) =
-        findExecutionHandle<Any, Any>(instance, method).get().invoke()
-
     @Test
     fun `part1 example result`() {
         Assertions.assertThat(exampleInstance.part1()).isEqualTo(part1Example)
diff --git a/2021/src/test/kotlin/Day04Test.kt b/2021/src/test/kotlin/Day04Test.kt
index 83468ea..2356327 100644
--- a/2021/src/test/kotlin/Day04Test.kt
+++ b/2021/src/test/kotlin/Day04Test.kt
@@ -24,8 +24,8 @@ class Day04Test : BaseDayTest(4) {
     """.trimIndent()
 
     override val part1Example = 4512
-    override val part2Example = 1924
-
     override val part1Answer = 87456
+
+    override val part2Example = 1924
     override val part2Answer = 15561
 }