Generalize rebase-errors.py so it works for other files.

net/data/verify_certificate_chain_unittest/rebase-errors.py

 #!/usr/bin/python
 # Copyright (c) 2016 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Helper script to update the test error expectations based on actual results.
 
 This is useful for regenerating test expectations after making changes to the
 error format.
 
 To use this run the affected tests, and then pass the input to this script
 (either via stdin, or as the first argument). For instance:
 
   $ ./out/Release/net_unittests --gtest_filter="*VerifyCertificateChain*" | \
      net/data/verify_certificate_chain_unittest/rebase-errors.py
 
-The script will search the unit-test (results.txt in above example) and look
-for failure lines and the corresponding actual error string.
+The script works by scanning the stdout looking for gtest failures when
+comparing "errors.ToDebugString()". The C++ test side should have been
+instrumented to dump out the test file's path on mismatch.
 
-It will then go and update the corresponding .pem and .py file.
+This script will then update the corresponding file(s) -- a .pem file, and
+possibly an accompanying .py file.
 """
 
 import common
-import glob
 import os
 import sys
 import re
 
 
+# Regular expression to find the failed errors in test stdout.
+#  * Group 1 of the match is the actual error text (backslash-escaped)
+#  * Group 2 of the match is file path (relative to //src) where the expected
+#    errors were read from.
+failed_test_regex = re.compile(r"""
+Value of: errors.ToDebugString\(\)
+  Actual: "(.*)"
+(?:.|\n)+?
+Test file: (.*)
+""", re.MULTILINE)
+
+
+# Regular expression to find the ERRORS block (and any text above it) in a PEM
+# file. The assumption is that ERRORS is not the very first block in the file
+# (since it looks for an -----END to precede it).
+#  * Group 1 of the match is the ERRORS block content and any comments
+#    immediately above it.
+errors_block_regex = re.compile(r""".*
+-----END .*?-----
+
+(.*?
+-----BEGIN ERRORS-----
+.*?
+-----END ERRORS-----
+)""", re.MULTILINE | re.DOTALL)
+
+
 def read_file_to_string(path):
   """Reads a file entirely to a string"""
   with open(path, 'r') as f:
     return f.read()
 
 
 def write_string_to_file(data, path):
   """Writes a string to a file"""
   print "Writing file %s ..." % (path)
   with open(path, "w") as f:
     f.write(data)
 
 
-def get_file_paths_for_test(test_name):
-  """Returns the file paths (as a tuple) that define a particular unit test.
-  For instance given test name 'IntermediateLacksBasicConstraints' it would
-  return the paths to:
+def get_py_path(pem_path):
+  """Returns the .py filepath used to generate the given .pem path, which may
+  or may not exist.
 
-   * intermediate-lacks-basic-constraints.pem,
-   * generate-intermediate-lacks-basic-constraints.py
-  """
-  # The directory that this python script is stored in.
-  base_dir = os.path.dirname(os.path.realpath(__file__))
-
-  # The C++ test name is just a camel case verson of the file name. Rather than
-  # converting directly from camel case to a file name, it is simpler to just
-  # scan the file list and see which matches. (Not efficient but good enough).
-  paths = glob.glob(os.path.join(base_dir, '*.pem'))
-
-  for pem_path in paths:
-    file_name = os.path.basename(pem_path)
-    file_name_no_extension = os.path.splitext(file_name)[0]
-
-    # Strip the hyphens in file name to bring it closer to the camel case.
-    transformed = file_name_no_extension.replace('-', '')
-
-    # Now all that differs is the case.
-    if transformed.lower() == test_name.lower():
-      py_file_name = 'generate-' + file_name_no_extension + '.py'
-      py_path = os.path.join(base_dir, py_file_name)
-      return (pem_path, py_path)
-
-  return None
+  Some test files (notably those in verify_certificate_chain_unittest/ have a
+  "generate-XXX.py" script that builds the "XXX.pem" file. Build the path to
+  the corresponding "generate-XXX.py" (which may or may not exist)."""
+  file_name = os.path.basename(pem_path)
+  file_name_no_extension = os.path.splitext(file_name)[0]
+  py_file_name = 'generate-' + file_name_no_extension + '.py'
+  return os.path.join(os.path.dirname(pem_path), py_file_name)
 
 
 def replace_string(original, start, end, replacement):
   """Replaces the specified range of |original| with |replacement|"""
   return original[0:start] + replacement + original[end:]
 
 
 def fixup_pem_file(path, actual_errors):
   """Updates the ERRORS block in the test .pem file"""
   contents = read_file_to_string(path)
 
-  # This assumes that ERRORS is the last thing in file, and comes after the
-  # VERIFY_RESULT block.
-  kEndVerifyResult = '-----END VERIFY_RESULT-----'
-  contents = contents[0:contents.index(kEndVerifyResult)]
-  contents += kEndVerifyResult
-  contents += '\n'
-  contents += '\n'
-  contents += common.text_data_to_pem('ERRORS', actual_errors)
+  m = errors_block_regex.search(contents)
+
+  if not m:
+    print "Couldn't find ERRORS block in %s" % (path)
+    return
+
+  contents = replace_string(contents, m.start(1), m.end(1),
+                            common.text_data_to_pem('ERRORS', actual_errors))
 
   # Update the file.
   write_string_to_file(contents, path)
 
 
 def fixup_py_file(path, actual_errors):
   """Replaces the 'errors = XXX' section of the test's python script"""
   contents = read_file_to_string(path)
 
   # This assumes that the errors variable uses triple quotes.
-  prog = re.compile(r'^errors = """(.*)"""', re.MULTILINE | re.DOTALL)
+  prog = re.compile(r'^errors = """(.*?)"""', re.MULTILINE | re.DOTALL)
   result = prog.search(contents)
 
   # Replace the stuff in between the triple quotes with the actual errors.
   contents = replace_string(contents, result.start(1), result.end(1),
                             actual_errors)
 
   # Update the file.
   write_string_to_file(contents, path)
 
 
-def fixup_test(test_name, actual_errors):
-  """Updates the test files used by |test_name|, setting the expected error to
+def get_src_root():
+  """Returns the path to the enclosing //src directory. This assumes the
+  current script is inside the source tree."""
+  cur_dir = os.path.dirname(os.path.realpath(__file__))
+
+  while True:
+    parent_dir, dirname = os.path.split(cur_dir)
+    # Check if it looks like the src/ root.
+    if dirname == "src" and os.path.isdir(os.path.join(cur_dir, "net")):
+      return cur_dir
+    if not parent_dir or parent_dir == cur_dir:
+      break
+    cur_dir = parent_dir
+
+  print "Couldn't find src dir"
+  sys.exit(1)
+
+
+def get_abs_path(rel_path):
+  """Converts |rel_path| (relative to src) to a full path"""
+  return os.path.join(get_src_root(), rel_path)
+
+
+def fixup_errors_for_file(actual_errors, pem_path):
+  """Updates the errors in |test_file_path| (.pem file) to match
   |actual_errors|"""
 
-  # Determine the paths for the corresponding *.pem file and generate-*.py
-  pem_path, py_path = get_file_paths_for_test(test_name)
+  fixup_pem_file(pem_path, actual_errors)
 
-  fixup_pem_file(pem_path, actual_errors)
-  fixup_py_file(py_path, actual_errors)
-
-
-kTestNamePattern = (r'^\[ RUN      \] VerifyCertificateChain/'
-                    'VerifyCertificateChainSingleRootTest/0\.(.*)$')
-kValueOfLine = 'Value of: errors.ToDebugString()'
-kActualPattern = '^  Actual: "(.*)"$'
+  # If the test has a generator script update it too.
+  py_path = get_py_path(pem_path)
+  if os.path.isfile(py_path):
+    fixup_py_file(py_path, actual_errors)
 
 
 def main():
   if len(sys.argv) > 2:
     print 'Usage: %s [path-to-unittest-stdout]' % (sys.argv[0])
     sys.exit(1)
 
   # Read the input either from a file, or from stdin.
   test_stdout = None
   if len(sys.argv) == 2:
     test_stdout = read_file_to_string(sys.argv[1])
   else:
     print 'Reading input from stdin...'
     test_stdout = sys.stdin.read()
 
-  lines = test_stdout.split('\n')
-
-  # Iterate over each line of the unit test stdout.
-  for i in range(len(lines) - 3):
-    # Figure out the name of the test.
-    m = re.search(kTestNamePattern, lines[i])
-    if not m:
-      continue
-    test_name = m.group(1)
-
-    # Confirm that it is a failure having to do with the errors.
-    if lines[i + 2] != kValueOfLine:
-      continue
-
-    # Get the actual error text (which in gtest output is escaped).
-    m = re.search(kActualPattern, lines[i + 3])
-    if not m:
-      continue
-    actual = m.group(1)
-    actual = actual.decode('string-escape')
-
-    fixup_test(test_name, actual)
+  for m in failed_test_regex.finditer(test_stdout):
+    actual_errors = m.group(1)
+    actual_errors = actual_errors.decode('string-escape')
+    relative_test_path = m.group(2)
+    fixup_errors_for_file(actual_errors, get_abs_path(relative_test_path))
 
 
 if __name__ == "__main__":
   main()