removes some warning and unused objects

test/java/net/yacy/cora/document/feed/RSSFeedTest.java

@@ -1,8 +1,8 @@
 package net.yacy.cora.document.feed;
 
-import java.io.IOException;
+import static org.junit.Assert.assertNotNull;
+
 import org.junit.Test;
-import static org.junit.Assert.*;
 
 public class RSSFeedTest {
 
@@ -10,7 +10,7 @@ public class RSSFeedTest {
      * Test of getChannel method, of class RSSFeed.
      */
     @Test
-    public void testGetChannel() throws IOException {
+    public void testGetChannel() {
         RSSFeed feed = new RSSFeed(Integer.MAX_VALUE);
 
         // channel is required in RSS 2.0 and accessed in code w/o != null checks

test/java/net/yacy/cora/document/id/DigestURLHashPerfTest.java

@@ -62,7 +62,7 @@ public class DigestURLHashPerfTest {
 
 		System.out.println(urls.size() + " URLs loaded from " + inFile.getAbsolutePath());
 
-		try (OutputStream outStream = args.length >= 2 ? new FileOutputStream(args[1]) : new NullOutputStream();
+		try (OutputStream outStream = args.length >= 2 ? new FileOutputStream(args[1]) : NullOutputStream.NULL_OUTPUT_STREAM;
 				OutputStreamWriter writer = new OutputStreamWriter(outStream, StandardCharsets.UTF_8.name());
 				BufferedWriter out = new BufferedWriter(writer);) {
 

test/java/net/yacy/search/ranking/ReferenceOrderTest.java

@@ -1,16 +1,18 @@
 package net.yacy.search.ranking;
 
+import static org.junit.Assert.assertTrue;
+
 import java.io.File;
 import java.io.IOException;
 import java.net.MalformedURLException;
+
+import org.apache.solr.common.SolrInputDocument;
+import org.junit.Test;
+
 import net.yacy.cora.document.analysis.Classification;
 import net.yacy.cora.document.id.DigestURL;
-import net.yacy.cora.util.SpaceExceededException;
 import net.yacy.kelondro.data.meta.URIMetadataNode;
 import net.yacy.search.schema.CollectionConfiguration;
-import org.apache.solr.common.SolrInputDocument;
-import static org.junit.Assert.assertTrue;
-import org.junit.Test;
 
 public class ReferenceOrderTest {
 
@@ -20,7 +22,7 @@ public class ReferenceOrderTest {
      * (only used if no Solr score supplied)
      */
     @Test
-    public void testCardinal_URIMetadataNode() throws MalformedURLException, IOException, SpaceExceededException {
+    public void testCardinal_URIMetadataNode() throws MalformedURLException, IOException {
         File config = new File("defaults/solr.collection.schema");
         CollectionConfiguration cc = new CollectionConfiguration(config, true);