diff --git a/2021/src/test/kotlin/BaseDayTest.kt b/2021/src/test/kotlin/BaseDayTest.kt
new file mode 100644
index 0000000..472d7af
--- /dev/null
+++ b/2021/src/test/kotlin/BaseDayTest.kt
@@ -0,0 +1,65 @@
+package be.vandewalleh.aoc.days
+
+import be.vandewalleh.aoc.utils.factory.findDayDefinition
+import be.vandewalleh.aoc.utils.factory.registerExampleLoader
+import io.micronaut.context.BeanContext
+import org.assertj.core.api.Assertions
+import org.junit.jupiter.api.AfterAll
+import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.TestInstance
+
+@TestInstance(TestInstance.Lifecycle.PER_CLASS)
+abstract class BaseDayTest(day: Int) {
+
+    abstract val example: String
+
+    abstract val part1Example: Any
+    abstract val part2Example: Any
+
+    abstract val part1Answer: Any
+    abstract val part2Answer: Any
+
+    private val ctx = lazy {
+        BeanContext.run()
+    }
+
+    val instance: Any by lazy { ctx.value.getBean(ctx.value.findDayDefinition(day)) }
+
+
+    private val exampleCtx = lazy {
+        BeanContext.build()
+            .apply { registerExampleLoader(example) }
+            .start()
+    }
+
+    val exampleInstance: Any by lazy { exampleCtx.value.getBean(exampleCtx.value.findDayDefinition(day)) }
+
+    @AfterAll
+    fun `after all`() {
+        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(ctx.value.run(exampleInstance, "part1")).isEqualTo(part1Example)
+    }
+
+    @Test
+    fun `part1 result`() {
+        Assertions.assertThat(ctx.value.run(instance, "part1")).isEqualTo(part1Answer)
+    }
+
+    @Test
+    fun `part2 example result`() {
+        Assertions.assertThat(ctx.value.run(exampleInstance, "part2")).isEqualTo(part2Example)
+    }
+
+    @Test
+    fun `part2 result`() {
+        Assertions.assertThat(ctx.value.run(instance, "part2")).isEqualTo(part2Answer)
+    }
+
+}
diff --git a/2021/src/test/kotlin/Day01Test.kt b/2021/src/test/kotlin/Day01Test.kt
new file mode 100644
index 0000000..9340260
--- /dev/null
+++ b/2021/src/test/kotlin/Day01Test.kt
@@ -0,0 +1,22 @@
+package be.vandewalleh.aoc.days
+
+class Day01Test : BaseDayTest(1) {
+    override val example = """
+        199
+        200
+        208
+        210
+        200
+        207
+        240
+        269
+        260
+        263
+    """.trimIndent()
+
+    override val part1Example = 7
+    override val part2Example = 5
+
+    override val part1Answer = 1559
+    override val part2Answer = 1600
+}
diff --git a/utils/src/main/kotlin/be/vandewalleh/aoc/utils/factory/DayFactory.kt b/utils/src/main/kotlin/be/vandewalleh/aoc/utils/factory/DayFactory.kt
index 87da20d..6515f0d 100644
--- a/utils/src/main/kotlin/be/vandewalleh/aoc/utils/factory/DayFactory.kt
+++ b/utils/src/main/kotlin/be/vandewalleh/aoc/utils/factory/DayFactory.kt
@@ -15,7 +15,7 @@ fun BeanContext.findDayDefinition(day: Int): BeanDefinition<*>? = allBeanDefinit
 inline fun <reified T> createDay() = createDay(T::class.java)
 
 // A custom resourceLoader that returns a string should be more appropriate but ¯\_(ツ)_/¯
-private fun BeanContext.registerExampleLoader(example: String) {
+fun BeanContext.registerExampleLoader(example: String) {
     registerSingleton(TempFileResourceLoader(File.createTempFile("aoc-example", ".txt").apply {
         writeText(example)
     }))