Enabling and fixing CheckNewlineAtTheEndOfProtoFiles

This check has been skipped during the migration from src/webrtc to
src. It was also reporting false positives. Now it should be fixed.

NOTRY=True

Bug: chromium:611808
Change-Id: Id8567dd92099e75ac35351f053829deebf28a9d1
Reviewed-on: https://webrtc-review.googlesource.com/1580
Reviewed-by: Henrik Kjellander <kjellander@webrtc.org>
Reviewed-by: Henrik Kjellander <kjellander@google.com>
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#19887}

presubmit_test.py

@@ -8,10 +8,14 @@
 #  in the file PATENTS.  All contributing project authors may
 #  be found in the AUTHORS file in the root of the source tree.
 
+import os
+import shutil
+import tempfile
+import textwrap
 import unittest
 
 import PRESUBMIT
-from presubmit_test_mocks import MockInputApi, MockOutputApi
+from presubmit_test_mocks import MockInputApi, MockOutputApi, MockFile
 
 
 class CheckBugEntryField(unittest.TestCase):
@@ -44,5 +48,49 @@ class CheckBugEntryField(unittest.TestCase):
     self.assertEqual(0, len(errors))
 
 
+class CheckNewlineAtTheEndOfProtoFiles(unittest.TestCase):
+
+  def setUp(self):
+    self.tmp_dir = tempfile.mkdtemp()
+    self.proto_file_path = os.path.join(self.tmp_dir, 'foo.proto')
+    self.input_api = MockInputApi()
+    self.output_api = MockOutputApi()
+
+  def tearDown(self):
+    shutil.rmtree(self.tmp_dir, ignore_errors=True)
+
+  def testErrorIfProtoFileDoesNotEndWithNewline(self):
+    self.__GenerateProtoWithoutNewlineAtTheEnd()
+    self.input_api.files = [MockFile(self.proto_file_path)]
+    errors = PRESUBMIT.CheckNewlineAtTheEndOfProtoFiles(self.input_api,
+                                                        self.output_api)
+    self.assertEqual(1, len(errors))
+    self.assertEqual(
+        'File %s must end with exactly one newline.' % self.proto_file_path,
+        str(errors[0]))
+
+  def testNoErrorIfProtoFileEndsWithNewline(self):
+    self.__GenerateProtoWithNewlineAtTheEnd()
+    self.input_api.files = [MockFile(self.proto_file_path)]
+    errors = PRESUBMIT.CheckNewlineAtTheEndOfProtoFiles(self.input_api,
+                                                        self.output_api)
+    self.assertEqual(0, len(errors))
+
+  def __GenerateProtoWithNewlineAtTheEnd(self):
+    with open(self.proto_file_path, 'w') as f:
+      f.write(textwrap.dedent("""
+        syntax = "proto2";
+        option optimize_for = LITE_RUNTIME;
+        package webrtc.audioproc;
+      """))
+
+  def __GenerateProtoWithoutNewlineAtTheEnd(self):
+    with open(self.proto_file_path, 'w') as f:
+      f.write(textwrap.dedent("""
+        syntax = "proto2";
+        option optimize_for = LITE_RUNTIME;
+        package webrtc.audioproc;"""))
+
+
 if __name__ == '__main__':
   unittest.main()