UT helped debugging the problem.

but it's disabled as it really scrapes the spring repo

nexus-core/src/test/java/org/sonatype/nexus/proxy/maven/routing/internal/scrape/AmazonS3LiveIndexScraperTest.java

@@ -0,0 +1,71 @@
+/*
+ * Sonatype Nexus (TM) Open Source Version
+ * Copyright (c) 2007-2012 Sonatype, Inc.
+ * All rights reserved. Includes the third-party code listed at http://links.sonatype.com/products/nexus/oss/attributions.
+ *
+ * This program and the accompanying materials are made available under the terms of the Eclipse Public License Version 1.0,
+ * which accompanies this distribution and is available at http://www.eclipse.org/legal/epl-v10.html.
+ *
+ * Sonatype Nexus (TM) Professional Version is available from Sonatype, Inc. "Sonatype" and "Sonatype Nexus" are trademarks
+ * of Sonatype, Inc. Apache Maven is a trademark of the Apache Software Foundation. M2eclipse is a trademark of the
+ * Eclipse Foundation. All other trademarks are the property of their respective owners.
+ */
+package org.sonatype.nexus.proxy.maven.routing.internal.scrape;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.is;
+import static org.hamcrest.Matchers.notNullValue;
+import static org.mockito.Mockito.when;
+
+import java.util.List;
+
+import org.apache.http.client.HttpClient;
+import org.apache.http.impl.client.DefaultHttpClient;
+import org.junit.Before;
+import org.junit.Ignore;
+import org.junit.Test;
+import org.mockito.Mock;
+import org.sonatype.nexus.proxy.maven.MavenProxyRepository;
+import org.sonatype.sisu.litmus.testsupport.TestSupport;
+
+@Ignore( "This test really goes remotely and would try to scrape Springsource external repository." )
+public class AmazonS3LiveIndexScraperTest
+    extends TestSupport
+{
+    @Mock
+    private MavenProxyRepository mavenProxyRepository;
+
+    private AmazonS3IndexScraper s3scraper;
+
+    @Before
+    public void prepare()
+        throws Exception
+    {
+        s3scraper = new AmazonS3IndexScraper();
+    }
+
+    /**
+     * This test will go remote for true and scrape Springsource External bundles repository, that should take about 20+
+     * "paged" request (every page is 1000 entries limited by S3), and will take about a minute to execute.
+     * 
+     * @throws Exception
+     */
+    @Test
+    public void springExternalRepository()
+        throws Exception
+    {
+        final HttpClient httpClient = new DefaultHttpClient();
+        final String repoRoot = "http://repository.springsource.com/maven/bundles/external/";
+        when( mavenProxyRepository.getRemoteUrl() ).thenReturn( repoRoot );
+        final ScrapeContext context = new ScrapeContext( mavenProxyRepository, httpClient, 2 );
+        final Page page = Page.getPageFor( context, repoRoot );
+        s3scraper.scrape( context, page );
+        assertThat( context.isStopped(), is( true ) );
+        assertThat( context.isSuccessful(), is( true ) );
+        assertThat( context.getPrefixSource(), notNullValue() );
+        final List<String> entries = context.getPrefixSource().readEntries();
+        assertThat( entries, notNullValue() );
+        assertThat( entries.size(), equalTo( 152 ) );
+    }
+}