fix NPE on MultiProtocolURL on url with parameter value and '='

in getAttribute
- added test case for it

source/net/yacy/cora/document/id/MultiProtocolURL.java

@@ -1007,6 +1007,11 @@ public class MultiProtocolURL implements Serializable, Comparable<MultiProtocolU
         return token;
     }
 
+    /**
+     * Evaluates url search part and returns attribute '=' value pairs
+     *
+     * @return map key=attribue name, value=string after '='
+     */
     public Map<String, String> getAttributes() {
         Map<String, String > map = new LinkedHashMap<>();
         if (this.searchpart == null) return map;
@@ -1016,7 +1021,7 @@ public class MultiProtocolURL implements Serializable, Comparable<MultiProtocolU
             if (p != -1) {
                 map.put(element.substring(0, p), element.substring(p + 1));
             } else {
-                map.put(element.substring(0, p), "");
+                if (!element.isEmpty()) map.put(element, "");
             }
         }
         return map;

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

@@ -4,6 +4,7 @@ import static org.junit.Assert.*;
 
 import java.net.MalformedURLException;
 import java.util.LinkedHashMap;
+import java.util.Map;
 import java.util.TreeSet;
 
 import org.junit.Test;
@@ -158,7 +159,7 @@ public class MultiProtocolURLTest {
 
         for (String[] testString : testStrings) {
             // desired conversion result
-            System.out.print("orig uri: " + testString[0]);
+            System.out.print("toNormalform orig uri: " + testString[0]);
             String shouldBe = testString[1];
             // conversion result
             String resultUrl = new MultiProtocolURL(testString[0]).toNormalform(true);
@@ -167,6 +168,30 @@ public class MultiProtocolURLTest {
             System.out.println(" -> " + resultUrl);
         }
     }
+
+    /**
+     * Test of getAttribute method, of class MultiProtocolURL.
+     */
+    @Test
+    public void testGetAttribute() throws Exception {
+        // some test url/uri with problems in the past
+        String[][] testStrings = new String[][]{
+            // teststring , expectedresult
+            new String[]{"http://yacy.net?&test", "test"}
+        };
+
+        for (String[] testString : testStrings) {
+            // desired conversion result
+            System.out.print("test getAttribute: " + testString[0]);
+            String shouldBe = testString[1];
+
+            MultiProtocolURL resultUrl = new MultiProtocolURL(testString[0]);
+            Map<String, String> attr = resultUrl.getAttributes();
+
+            assertEquals("", attr.get(shouldBe));
+            System.out.println(" -> " + resultUrl.toNormalform(false));
+        }
+    }
 }