run_py_unittests: Require files to be formatted by yapf.

- Will make upcoming refactors easier w/ fewer spurious diffs.

BUG=None
TEST=CQ

Change-Id: I4a11055dbf762e37f56d4e70dec853140bca4acb
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/config/+/2222287
Commit-Queue: Sean McAllister <smcallis@google.com>
Tested-by: Andrew Lamb <andrewlamb@chromium.org>
Auto-Submit: Andrew Lamb <andrewlamb@chromium.org>
Reviewed-by: Sean McAllister <smcallis@google.com>
diff --git a/payload_utils/checker/io_utils_test.py b/payload_utils/checker/io_utils_test.py
index 08d08ac..0d2727d 100644
--- a/payload_utils/checker/io_utils_test.py
+++ b/payload_utils/checker/io_utils_test.py
@@ -25,11 +25,9 @@
 
     os.mkdir(os.path.join(repo_path, 'generated'))
 
-    self.config_path = os.path.join(repo_path, 'generated',
-                                    'config.jsonproto')
-    json_output = json_format.MessageToJson(self.config,
-                                            sort_keys=True,
-                                            use_integers_for_enums=True)
+    self.config_path = os.path.join(repo_path, 'generated', 'config.jsonproto')
+    json_output = json_format.MessageToJson(
+        self.config, sort_keys=True, use_integers_for_enums=True)
     with open(self.config_path, 'w') as f:
       print(json_output, file=f)