Index: trunk/test/functional/org/openstreetmap/josm/gui/mappaint/StyleCacheTest.java
===================================================================
--- trunk/test/functional/org/openstreetmap/josm/gui/mappaint/StyleCacheTest.java	(revision 11776)
+++ trunk/test/functional/org/openstreetmap/josm/gui/mappaint/StyleCacheTest.java	(revision 11777)
@@ -53,9 +53,9 @@
     @Rule
     @SuppressFBWarnings(value = "URF_UNREAD_PUBLIC_OR_PROTECTED_FIELD")
-    public JOSMTestRules test = new JOSMTestRules().preferences().platform().projection();
+    public JOSMTestRules test = new JOSMTestRules().preferences().platform().projection().mapStyles();
 
     /**
      * Load the test data that is required.
-     * @throws Exception
+     * @throws Exception It an error occurred during load.
      */
     @BeforeClass
@@ -96,5 +96,4 @@
         nc = new MapView(Main.getLayerManager(), null);
         nc.setBounds(0, 0, IMG_WIDTH, IMG_HEIGHT);
-        MapPaintStyles.readFromPreferences();
     }
 
Index: trunk/test/unit/org/openstreetmap/josm/testutils/JOSMTestRules.java
===================================================================
--- trunk/test/unit/org/openstreetmap/josm/testutils/JOSMTestRules.java	(revision 11776)
+++ trunk/test/unit/org/openstreetmap/josm/testutils/JOSMTestRules.java	(revision 11777)
@@ -15,4 +15,5 @@
 import org.openstreetmap.josm.Main;
 import org.openstreetmap.josm.data.projection.Projections;
+import org.openstreetmap.josm.gui.mappaint.MapPaintStyles;
 import org.openstreetmap.josm.gui.util.GuiHelper;
 import org.openstreetmap.josm.io.OsmApi;
@@ -44,4 +45,5 @@
     private boolean commands;
     private boolean allowMemoryManagerLeaks;
+    private boolean useMapStyles;
 
     /**
@@ -153,4 +155,15 @@
     public JOSMTestRules memoryManagerLeaks() {
         allowMemoryManagerLeaks = true;
+        return this;
+    }
+
+    /**
+     * Use map styles in this test.
+     * @return this instance, for easy chaining
+     * @since 11777
+     */
+    public JOSMTestRules mapStyles() {
+        preferences();
+        useMapStyles = true;
         return this;
     }
@@ -233,4 +246,9 @@
         if (platform) {
             Main.determinePlatformHook();
+        }
+
+        if (useMapStyles) {
+            // Reset the map paint styles.
+            MapPaintStyles.readFromPreferences();
         }