Index: trunk/test/unit/org/openstreetmap/josm/data/osm/MultipolygonBuilderTest.java
===================================================================
--- trunk/test/unit/org/openstreetmap/josm/data/osm/MultipolygonBuilderTest.java	(revision 9476)
+++ trunk/test/unit/org/openstreetmap/josm/data/osm/MultipolygonBuilderTest.java	(revision 9476)
@@ -0,0 +1,48 @@
+// License: GPL. For details, see LICENSE file.
+package org.openstreetmap.josm.data.osm;
+
+import java.io.FileInputStream;
+import java.io.InputStream;
+
+import org.junit.BeforeClass;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.Timeout;
+import org.openstreetmap.josm.JOSMFixture;
+import org.openstreetmap.josm.TestUtils;
+import org.openstreetmap.josm.io.Compression;
+import org.openstreetmap.josm.io.OsmReader;
+
+/**
+ * Unit tests of the {@code MultipolygonBuilder} class.
+ */
+public class MultipolygonBuilderTest {
+
+    /**
+     * Global timeout applied to all test methods.
+     */
+    @Rule
+    public Timeout globalTimeout = Timeout.seconds(15);
+
+    /**
+     * Setup test.
+     */
+    @BeforeClass
+    public static void init() {
+        JOSMFixture.createUnitTestFixture().init();
+    }
+
+    /**
+     * Non-regression test for ticket #12060.
+     * @throws Exception if an error occurs
+     */
+    @Test
+    public void testTicket12376() throws Exception {
+        try (InputStream is = new FileInputStream(TestUtils.getRegressionDataFile(12376, "multipolygon_hang.osm.bz2"))) {
+            DataSet ds = OsmReader.parseDataSet(Compression.BZIP2.getUncompressedInputStream(is), null);
+            for (Relation r : ds.getRelations()) {
+                new MultipolygonBuilder().makeFromWays(r.getMemberPrimitives(Way.class));
+            }
+        }
+    }
+}