bpo-31908: Fix output of cover files for trace module command-line tool. (GH-4205)

Previously emitted cover files only when --missing option was used.

Author: selik

Lib/test/test_trace.py

@@ -2,6 +2,7 @@
 import sys
 from test.support import TESTFN, rmtree, unlink, captured_stdout
 from test.support.script_helper import assert_python_ok, assert_python_failure
+import textwrap
 import unittest
 
 import trace
@@ -365,6 +366,46 @@ def test_ignored(self):
  # Matched before.
  self.assertTrue(ignore.names(jn('bar', 'baz.py'), 'baz'))
 
+# Created for Issue 31908 -- CLI utility not writing cover files
+class TestCoverageCommandLineOutput(unittest.TestCase):
+
+ codefile = 'tmp.py'
+ coverfile = 'tmp.cover'
+
+ def setUp(self):
+ with open(self.codefile, 'w') as f:
+ f.write(textwrap.dedent('''\
+ x = 42
+ if []:
+ print('unreachable')
+ '''))
+
+ def tearDown(self):
+ unlink(self.codefile)
+ unlink(self.coverfile)
+
+ def test_cover_files_written_no_highlight(self):
+ argv = '-m trace --count'.split() + [self.codefile]
+ status, stdout, stderr = assert_python_ok(*argv)
+ self.assertTrue(os.path.exists(self.coverfile))
+ with open(self.coverfile) as f:
+ self.assertEqual(f.read(),
+ " 1: x = 42\n"
+ " 1: if []:\n"
+ " print('unreachable')\n"
+ )
+
+ def test_cover_files_written_with_highlight(self):
+ argv = '-m trace --count --missing'.split() + [self.codefile]
+ status, stdout, stderr = assert_python_ok(*argv)
+ self.assertTrue(os.path.exists(self.coverfile))
+ with open(self.coverfile) as f:
+ self.assertEqual(f.read(), textwrap.dedent('''\
+ 1: x = 42
+ 1: if []:
+ >>>>>> print('unreachable')
+ '''))
+
 class TestCommandLine(unittest.TestCase):
 
  def test_failures(self):

Lib/trace.py

@@ -73,9 +73,6 @@ def _unsettrace():
 
 PRAGMA_NOCOVER = "#pragma NO COVER"
 
-# Simple rx to find lines with no code.
-rx_blank = re.compile(r'^\s*(#.*)?$')
-
 class _Ignore:
  def __init__(self, modules=None, dirs=None):
  self._mods = set() if not modules else set(modules)
@@ -278,16 +275,15 @@ def write_results(self, show_missing=True, summary=False, coverdir=None):
  lnotab = _find_executable_linenos(filename)
  else:
  lnotab = {}
- if lnotab:
- source = linecache.getlines(filename)
- coverpath = os.path.join(dir, modulename + ".cover")
- with open(filename, 'rb') as fp:
- encoding, _ = tokenize.detect_encoding(fp.readline)
- n_hits, n_lines = self.write_results_file(coverpath, source,
- lnotab, count, encoding)
- if summary and n_lines:
- percent = int(100 * n_hits / n_lines)
- sums[modulename] = n_lines, percent, modulename, filename
+ source = linecache.getlines(filename)
+ coverpath = os.path.join(dir, modulename + ".cover")
+ with open(filename, 'rb') as fp:
+ encoding, _ = tokenize.detect_encoding(fp.readline)
+ n_hits, n_lines = self.write_results_file(coverpath, source,
+ lnotab, count, encoding)
+ if summary and n_lines:
+ percent = int(100 * n_hits / n_lines)
+ sums[modulename] = n_lines, percent, modulename, filename
 
 
  if summary and sums:
@@ -306,6 +302,7 @@ def write_results(self, show_missing=True, summary=False, coverdir=None):
 
  def write_results_file(self, path, lines, lnotab, lines_hit, encoding=None):
  """Return a coverage results file in path."""
+ # ``lnotab`` is a dict of executable lines, or a line number "table"
 
  try:
  outfile = open(path, "w", encoding=encoding)
@@ -324,17 +321,13 @@ def write_results_file(self, path, lines, lnotab, lines_hit, encoding=None):
  outfile.write("%5d: " % lines_hit[lineno])
  n_hits += 1
  n_lines += 1
- elif rx_blank.match(line):
- outfile.write(" ")
- else:
- # lines preceded by no marks weren't hit
- # Highlight them if so indicated, unless the line contains
+ elif lineno in lnotab and not PRAGMA_NOCOVER in line:
+ # Highlight never-executed lines, unless the line contains
  # #pragma: NO COVER
- if lineno in lnotab and not PRAGMA_NOCOVER in line:
- outfile.write(">>>>>> ")
- n_lines += 1
- else:
- outfile.write(" ")
+ outfile.write(">>>>>> ")
+ n_lines += 1
+ else:
+ outfile.write(" ")
  outfile.write(line.expandtabs(8))
 
  return n_hits, n_lines

Misc/NEWS.d/next/Library/2017-10-31.bpo-31908.g4xh8x.rst

@@ -0,0 +1,3 @@
+Fix output of cover files for ``trace`` module command-line tool.
+Previously emitted cover files only when ``--missing`` option was used.
+Patch by Michael Selik.