fix join_lines test

Author: qwcode

tests/unit/test_req_file.py

@@ -212,7 +212,7 @@ def test_parse_set_finder(self):
         assert finder.index_urls == ['url']
 
     def test_parse_content_join_lines(self):
-        content = '--index-url \\url'
+        content = '--index-url \\\n url'
         filename = 'filename'
         finder = stub()
         list(parse_content(filename, content, finder=finder))