added javadoc and unit test

scm-core/src/main/java/sonia/scm/repository/Repository.java

@@ -356,9 +356,7 @@ public class Repository extends BasicPropertiesAware implements ModelObject, Per
    * @since 1.17
    */
   public String createUrl(String baseUrl) {
-    String url = HttpUtil.append(baseUrl, type);
-
-    return HttpUtil.concatenate(url, namespace, name);
+    return HttpUtil.concatenate(baseUrl, type, namespace, name);
   }
 
   /**

scm-core/src/main/java/sonia/scm/util/HttpUtil.java

@@ -248,6 +248,14 @@ public final class HttpUtil
 
   //~--- methods --------------------------------------------------------------
 
+  /**
+   * Joins all path elements together separated by {@code {@link #SEPARATOR_PATH}}.
+   *
+   * @param pathElements path elements
+   *
+   * @return concatenated path
+   * @since 2.0.0
+   */
   public static String concatenate(String... pathElements) {
     return Arrays.stream(pathElements).reduce(HttpUtil::append).orElse("");
   }

scm-core/src/test/java/sonia/scm/util/HttpUtilTest.java

@@ -54,6 +54,18 @@ import javax.servlet.http.HttpServletRequest;
 public class HttpUtilTest
 {
 
+  @Test
+  public void concatenateTest() {
+    assertEquals(
+      "/scm/git/hitchhiker/tricia",
+      HttpUtil.concatenate("/scm", "git", "hitchhiker", "tricia")
+    );
+    assertEquals(
+      "scm/git/hitchhiker/tricia",
+      HttpUtil.concatenate("scm", "git", "hitchhiker", "tricia")
+    );
+  }
+
   /**
    * Method description
    *