diff --git a/app/src/main/java/org/blitzortung/android/map/overlay/color/ColorHandler.kt b/app/src/main/java/org/blitzortung/android/map/overlay/color/ColorHandler.kt
index da52f45f..b5a2a091 100644
--- a/app/src/main/java/org/blitzortung/android/map/overlay/color/ColorHandler.kt
+++ b/app/src/main/java/org/blitzortung/android/map/overlay/color/ColorHandler.kt
@@ -53,7 +53,7 @@ abstract class ColorHandler(private val preferences: SharedPreferences) {
     val colors: IntArray
         get() = getColors(target)
 
-    protected abstract fun getColors(target: ColorTarget): IntArray
+    abstract fun getColors(target: ColorTarget): IntArray
 
     fun getColorSection(referenceTime: Long, eventTime: Long, intervalDuration: Int): Int {
         val minutesPerColor = intervalDuration / colors.size
diff --git a/app/src/main/java/org/blitzortung/android/map/overlay/color/StrikeColorHandler.kt b/app/src/main/java/org/blitzortung/android/map/overlay/color/StrikeColorHandler.kt
index f8c4d181..af666d0f 100644
--- a/app/src/main/java/org/blitzortung/android/map/overlay/color/StrikeColorHandler.kt
+++ b/app/src/main/java/org/blitzortung/android/map/overlay/color/StrikeColorHandler.kt
@@ -33,10 +33,11 @@ open class StrikeColorHandler(preferences: SharedPreferences) : ColorHandler(pre
     }
 
     private fun getCachedStreetmapStrikeColors(strikeColors: IntArray): IntArray {
-        if (!streetmapColors.containsKey(strikeColors)) {
-            streetmapColors[strikeColors] = modifyBrightness(strikeColors, 0.8f)
+        return streetmapColors[strikeColors] ?: run {
+            val newValue = modifyBrightness(strikeColors, 0.8f)
+            streetmapColors[strikeColors] = newValue
+            newValue
         }
-        return streetmapColors[strikeColors]!!
     }
 
     override fun getTextColor(target: ColorTarget): Int {
diff --git a/app/src/test/java/org/blitzortung/android/map/overlay/color/StrikeColorHandlerTest.kt b/app/src/test/java/org/blitzortung/android/map/overlay/color/StrikeColorHandlerTest.kt
new file mode 100644
index 00000000..730a6bdb
--- /dev/null
+++ b/app/src/test/java/org/blitzortung/android/map/overlay/color/StrikeColorHandlerTest.kt
@@ -0,0 +1,61 @@
+package org.blitzortung.android.map.overlay.color
+
+import android.content.Context
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.Before
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.robolectric.RobolectricTestRunner
+import org.robolectric.RuntimeEnvironment
+import org.robolectric.annotation.Config
+
+@RunWith(RobolectricTestRunner::class)
+@Config(manifest = Config.NONE)
+class StrikeColorHandlerTest {
+
+    lateinit var strikeColorHandler: StrikeColorHandler;
+
+    @Before
+    fun setUp() {
+        val context = RuntimeEnvironment.getApplication()
+        val preferences = context.getSharedPreferences(context.packageName, Context.MODE_PRIVATE)
+
+        strikeColorHandler = StrikeColorHandler(preferences)
+
+    }
+
+    @Test
+    fun shouldReturnProperSatelliteColors() {
+        val colors = strikeColorHandler.getColors(ColorTarget.SATELLITE)
+
+        assertThat(colors).isEqualTo(ColorScheme.BLITZORTUNG.strikeColors)
+    }
+
+    @Test
+    fun shouldReturnProperSatelliteTextColor() {
+        val textColor = strikeColorHandler.getTextColor(ColorTarget.SATELLITE)
+
+        assertThat(textColor).isEqualTo(0xff000000.toInt())
+    }
+
+    @Test
+    fun shouldReturnProperStreetmapColors() {
+        val colors = strikeColorHandler.getColors(ColorTarget.STREETMAP)
+
+        assertThat(colors).containsExactly(
+            0xffcccccc.toInt(),
+            0xffcccc8d.toInt(),
+            0xffccb361.toInt(),
+            0xffcc8d4d.toInt(),
+            0xffc0664d.toInt(),
+            0xffb34040.toInt(),
+        )
+    }
+
+    @Test
+    fun shouldReturnProperStreetmapTextColor() {
+        val textColor = strikeColorHandler.getTextColor(ColorTarget.STREETMAP)
+
+        assertThat(textColor).isEqualTo(0xffffffff.toInt())
+    }
+}
\ No newline at end of file