[BasicNormalizer] Empty path to be normalized to / even if there is an (empty) query,

fixes #247

CHANGES.txt

@@ -1,7 +1,7 @@
 Crawler-Commons Change Log
 
 Current Development 1.1-SNAPSHOT (yyyy-mm-dd)
-- [BasicNormalizer] Trailing question mark in url query test should be added (Chaiavi, sebastian-nagel) #247
+- [BasicNormalizer] Empty path before query to be normalized to `/` (Chaiavi, sebastian-nagel) #247
 - EffectiveTldFinder to validate returned domain names for length restrictions (sebastian-nagel, Chaiavi) #251
 - Upgrade unit tests to use JUnit v5.x and parameterized tests (Chaiavi) #249, #253, #255
 - [Robots] Robots parser to always handle absolute sitemap URL even without valid base URL (pr3mar, kkrugler, sebastian-nagel) #240

src/main/java/crawlercommons/filters/basic/BasicURLNormalizer.java

@@ -130,6 +130,9 @@ public class BasicURLNormalizer extends URLFilter {
             if (file == null || "".equals(file)) { // add a slash
                 file = "/";
                 changed = true;
+            } else if (!file.startsWith("/")) {
+              file = "/" + file;
+              changed = true;
             }
 
             if (url.getRef() != null) { // remove the ref
@@ -196,6 +199,8 @@ public class BasicURLNormalizer extends URLFilter {
         // if path is empty return a single slash
         if (file.isEmpty()) {
             file = "/";
+        } else if (!file.startsWith("/")) {
+            file = "/" + file;
         }
 
         return file;

src/test/resources/normalizer/weirdToNormalizedUrls.csv

@@ -130,3 +130,5 @@ http:///////, http:/
 
 # empty path with trailing question mark (empty query) #247
 http://example.com?,http://example.com/?
+http://example.com?a=1,http://example.com/?a=1
+