Index: trunk/test/unit/org/openstreetmap/josm/data/validation/tests/MapCSSTagCheckerTest.java
===================================================================
--- trunk/test/unit/org/openstreetmap/josm/data/validation/tests/MapCSSTagCheckerTest.java	(revision 15979)
+++ trunk/test/unit/org/openstreetmap/josm/data/validation/tests/MapCSSTagCheckerTest.java	(revision 15981)
@@ -16,4 +16,5 @@
 import java.util.Set;
 
+import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
@@ -28,4 +29,6 @@
 import org.openstreetmap.josm.data.osm.OsmPrimitive;
 import org.openstreetmap.josm.data.osm.OsmUtils;
+import org.openstreetmap.josm.data.preferences.sources.ExtendedSourceEntry;
+import org.openstreetmap.josm.data.preferences.sources.ValidatorPrefHelper;
 import org.openstreetmap.josm.data.validation.Severity;
 import org.openstreetmap.josm.data.validation.TestError;
@@ -53,7 +56,17 @@
     public JOSMTestRules test = new JOSMTestRules().projection().territories().preferences();
 
+    /**
+     * Setup test.
+     */
+    @Before
+    public void setUp() {
+        MapCSSTagCheckerAsserts.clear();
+    }
+
     static MapCSSTagChecker buildTagChecker(String css) throws ParseException {
         final MapCSSTagChecker test = new MapCSSTagChecker();
-        test.checks.putAll("test", TagCheck.readMapCSS(new StringReader(css)).parseChecks);
+        Set<String> errors = new HashSet<>();
+        test.checks.putAll("test", TagCheck.readMapCSS(new StringReader(css), "", errors::add).parseChecks);
+        assertTrue(errors.toString(), errors.isEmpty());
         return test;
     }
@@ -182,9 +195,20 @@
         MapCSSTagChecker c = new MapCSSTagChecker();
         c.initialize();
-
+    }
+
+    /**
+     * Unit test for all {@link MapCSSTagChecker.TagTest} assertions.
+     * @throws Exception if an error occurs
+     */
+    @Test
+    public void testAssertions() throws Exception {
+        MapCSSTagChecker c = new MapCSSTagChecker();
         Set<String> assertionErrors = new LinkedHashSet<>();
-        for (Set<TagCheck> schecks : c.checks.values()) {
-            assertionErrors.addAll(MapCSSTagCheckerAsserts.checkAsserts(schecks));
-        }
+
+        // initialize
+        for (ExtendedSourceEntry entry : ValidatorPrefHelper.INSTANCE.getDefault()) {
+            c.addMapCSS(entry.url, assertionErrors::add);
+        }
+
         for (String msg : assertionErrors) {
             Logging.error(msg);
@@ -205,6 +229,5 @@
                 "  assertNoMatch: \"node amenity=restaurant\";\n" +
                 "}");
-        Set<String> errors = MapCSSTagCheckerAsserts.checkAsserts(test.checks.get("test"));
-        assertTrue(errors.toString(), errors.isEmpty());
+        assertNotNull(test);
     }
 
@@ -221,6 +244,5 @@
                 "  assertNoMatch: \"way name=Hauptstrasse\";\n" +
                 "}");
-        Set<String> errors = MapCSSTagCheckerAsserts.checkAsserts(test.checks.get("test"));
-        assertTrue(errors.toString(), errors.isEmpty());
+        assertNotNull(test);
     }