mimic urljoin behaviour when the first url is falsy

sylvinus · sylvinus · commit fda910309aa1 · 2016-07-18T12:27:15.000-04:00
diff --git a/tests/test_urlparse4.py b/tests/test_urlparse4.py
@@ -15,9 +15,17 @@
 
 ]
 
+urljoin_testcases = [
+    [("", "http://example.com"), "http://example.com"]
+]
+
 
 class UrlParse4TestCase(unittest.TestCase):
 
     def test_urlsplit(self):
         for case in urlsplit_testcases:
             self.assertEqual(urlparse.urlsplit(case[0]), case[1])
+
+    def test_urljoin(self):
+        for case in urljoin_testcases:
+            self.assertEqual(urlparse.urljoin(*case[0]), case[1])
diff --git a/urlparse4/cgurl.cpp b/urlparse4/cgurl.cpp
diff --git a/urlparse4/cgurl.pyx b/urlparse4/cgurl.pyx
@@ -160,7 +160,7 @@ def urlsplit(url):
     return SplitResultNamedTuple.__new__(SplitResultNamedTuple, url)
 
 def urljoin(bytes base, bytes url, allow_fragments=True):
-    if allow_fragments:
+    if allow_fragments and base:
         return GURL(base).Resolve(url).spec()
     else:
         return stdlib_urlparse.urljoin(base, url, allow_fragments=allow_fragments)
