added news entry

fixed test failure

Author: Patrik Kopkan

news/6340.feature

@@ -0,0 +1,3 @@
+Added a new option `--save-wheel-names` to command `wheel`.
+The option takes path and creates file in which
+is saved the basenames of wheels outputed by `wheel` command.

src/pip/_internal/commands/wheel.py

@@ -187,18 +187,17 @@ def run(self, options, args):
                             "Failed to build one or more wheels"
                         )
                     if wb.path_to_wheelnames is not None:
-                        if len(wb.wheel_filenames) != 0:
-                            entries_to_save = wb.wheel_filenames[::]
-                            for req in requirement_set.requirements.values():
-                                if req.link.filename.endswith('whl'):
-                                    entries_to_save.append(req.link.filename)
-
-                            with open(wb.path_to_wheelnames, 'w') as file:
-                                file.write(
-                                    os.linesep.join(
-                                        entries_to_save
-                                    ) + os.linesep
-                                )
+                        entries_to_save = wb.wheel_filenames[::]
+                        for req in requirement_set.requirements.values():
+                            if req.link.filename.endswith('whl'):
+                                entries_to_save.append(req.link.filename)
+
+                        with open(wb.path_to_wheelnames, 'w') as file:
+                            file.write(
+                                '\n'.join(
+                                    entries_to_save
+                                ) + '\n'
+                            )
 
                 except PreviousBuildDirError:
                     options.no_clean = True