diff --git a/app/src/test/java/de/jeanlucmakiola/clockula/ArchitectureRulesTest.kt b/app/src/test/java/de/jeanlucmakiola/clockula/ArchitectureRulesTest.kt
index 5cb6e2f..69309d3 100644
--- a/app/src/test/java/de/jeanlucmakiola/clockula/ArchitectureRulesTest.kt
+++ b/app/src/test/java/de/jeanlucmakiola/clockula/ArchitectureRulesTest.kt
@@ -46,6 +46,9 @@ class ArchitectureRulesTest {
             "TimerEntity",
             "WorldClockEntity",
             "LapEntity",
+            "AlarmStateEntity",
+            "AlarmStateDao",
+            "AlarmStateMapper",
             "AlarmDao",
             "TimerDao",
             "WorldClockDao",
@@ -66,4 +69,21 @@ class ArchitectureRulesTest {
 
         assertThat(offenders).isEmpty()
     }
+
+    @Test
+    fun `the alarm engine and its pure neighbours stay free of Android types`() {
+        val jvmTestable = kotlinSources.filter { file ->
+            val path = file.invariantSeparatorsPath
+            path.contains("de/jeanlucmakiola/clockula/domain/alarm/") ||
+                path.endsWith("de/jeanlucmakiola/clockula/alarm/AlarmEngine.kt") ||
+                path.endsWith("de/jeanlucmakiola/clockula/alarm/AlarmResolver.kt") ||
+                path.contains("de/jeanlucmakiola/clockula/system/")
+        }
+
+        val offenders = jvmTestable.filter { file ->
+            file.readLines().any { it.startsWith("import android.") || it.startsWith("import androidx.") }
+        }.map { it.invariantSeparatorsPath }
+
+        assertThat(offenders).isEmpty()
+    }
 }