More-precise no-coverage pragmas

9 files changed, 38 insertions, 21 deletions

diff --git a/coverage/misc.py b/coverage/misc.py
index 534ef179..cb9248d2 100644
--- a/coverage/misc.py
+++ b/coverage/misc.py
@@ -76,7 +76,7 @@ if env.TESTING:
                 return func(*args, **kwargs)
             return _wrapped
         return _decorator
-else:                                           # pragma: not covered
+else:                                           # pragma: not testing
     # We aren't using real PyContracts, so just define our decorators as
     # stunt-double no-ops.
     contract = dummy_decorator_with_args
@@ -152,7 +152,7 @@ def expensive(fn):
             return fn(self)
         return _wrapped
     else:
-        return fn                   # pragma: not covered
+        return fn                   # pragma: not testing
 
 
 def bool_or_none(b):
diff --git a/coverage/parser.py b/coverage/parser.py
index c44ba22e..6e9bd54a 100644
--- a/coverage/parser.py
+++ b/coverage/parser.py
@@ -138,7 +138,7 @@ class PythonParser(object):
 
         tokgen = generate_tokens(self.text)
         for toktype, ttext, (slineno, _), (elineno, _), ltext in tokgen:
-            if self.show_tokens:                # pragma: not covered
+            if self.show_tokens:                # pragma: debugging
                 print("%10s %5s %-20r %r" % (
                     tokenize.tok_name.get(toktype, toktype),
                     nice_pair((slineno, elineno)), ttext, ltext
diff --git a/metacov.ini b/metacov.ini
index 23806587..b25af6eb 100644
--- a/metacov.ini
+++ b/metacov.ini
@@ -14,11 +14,28 @@ source =
 # We set a different pragma so our code won't be confused with test code.
 exclude_lines =
     pragma: not covered
+
+    # Lines in test code that isn't covered: we are nested inside ourselves.
     pragma: nested
+
+    # Lines that are only executed when we are debugging coverage.py.
     def __repr__
-    raise AssertionError
     pragma: debugging
+
+    # Lines that are only executed when we are not testing coverage.py.
+    pragma: not testing
+
+    # Lines that we can't run during metacov.
+    pragma: no metacov
+
+    # These lines only happen if tests fail.
+    raise AssertionError
     pragma: only failure
+
+    # OS error conditions that we can't (or don't care to) replicate.
+    pragma: cant happen
+
+    # Jython needs special care.
     pragma: only jython
     skip.*Jython
 
diff --git a/tests/osinfo.py b/tests/osinfo.py
index f586c51c..094fb097 100644
--- a/tests/osinfo.py
+++ b/tests/osinfo.py
@@ -35,7 +35,7 @@ if env.WINDOWS:
             ctypes.sizeof(mem_struct)
         )
         if not ret:                 # pragma: part covered
-            return 0                # pragma: not covered
+            return 0                # pragma: cant happen
         return mem_struct.PrivateUsage
 
 elif env.LINUX:
@@ -50,13 +50,13 @@ elif env.LINUX:
             # Get pseudo file /proc/<pid>/status
             with open('/proc/%d/status' % os.getpid()) as t:
                 v = t.read()
-        except IOError:             # pragma: not covered
+        except IOError:             # pragma: cant happen
             return 0    # non-Linux?
         # Get VmKey line e.g. 'VmRSS:  9999  kB\n ...'
         i = v.index(key)
         v = v[i:].split(None, 3)
         if len(v) < 3:              # pragma: part covered
-            return 0                # pragma: not covered
+            return 0                # pragma: cant happen
         # Convert Vm value to bytes.
         return int(float(v[1]) * _scale[v[2].lower()])
 
diff --git a/tests/test_arcs.py b/tests/test_arcs.py
index de59bf21..7df623bf 100644
--- a/tests/test_arcs.py
+++ b/tests/test_arcs.py
@@ -408,7 +408,7 @@ class LoopArcTest(CoverageTest):
 
     def test_other_comprehensions(self):
         if env.PYVERSION < (2, 7):
-            self.skipTest("No set or dict comprehensions before 2.7")       # pragma: not covered
+            self.skipTest("No set or dict comprehensions before 2.7")
         # Set comprehension:
         self.check_coverage("""\
             o = ((1,2), (3,4))
@@ -432,7 +432,7 @@ class LoopArcTest(CoverageTest):
 
     def test_multiline_dict_comp(self):
         if env.PYVERSION < (2, 7):
-            self.skipTest("No set or dict comprehensions before 2.7")       # pragma: not covered
+            self.skipTest("No set or dict comprehensions before 2.7")
         if env.PYVERSION < (3, 5):
             arcz = "-42 2B B-4   2-4"
         else:
diff --git a/tests/test_farm.py b/tests/test_farm.py
index 4a80be47..8e497363 100644
--- a/tests/test_farm.py
+++ b/tests/test_farm.py
@@ -119,7 +119,7 @@ class FarmTestCase(ModuleAwareMixin, SysPathAwareMixin, unittest.TestCase):
             glo['clean'] = clean
         else:
             glo = dict((fn, globals()[fn]) for fn in fns)
-            if self.dont_clean:                 # pragma: not covered
+            if self.dont_clean:                 # pragma: debugging
                 glo['clean'] = noop
 
         with change_dir(self.dir):
@@ -328,7 +328,7 @@ def clean(cleandir):
         if os.path.exists(cleandir):
             try:
                 shutil.rmtree(cleandir)
-            except OSError:         # pragma: not covered
+            except OSError:         # pragma: cant happen
                 if tries == 1:
                     raise
                 else:
@@ -369,7 +369,7 @@ def scrub(strdata, scrubs):
     return strdata
 
 
-def main():     # pragma: not covered
+def main():     # pragma: debugging
     """Command-line access to farm tests.
 
     Commands:
@@ -400,5 +400,5 @@ def main():     # pragma: not covered
         print(main.__doc__)
 
 # So that we can run just one farm run.py at a time.
-if __name__ == '__main__':          # pragma: not covered
+if __name__ == '__main__':          # pragma: debugging
     main()
diff --git a/tests/test_oddball.py b/tests/test_oddball.py
index fe841bd5..1cdadf6f 100644
--- a/tests/test_oddball.py
+++ b/tests/test_oddball.py
@@ -506,7 +506,7 @@ class GettraceTest(CoverageTest):
         )
 
     @pytest.mark.expensive
-    def test_atexit_gettrace(self):             # pragma: not covered
+    def test_atexit_gettrace(self):             # pragma: no metacov
         # This is not a test of coverage at all, but of our understanding
         # of this edge-case behavior in various Pythons.
         if env.METACOV:
diff --git a/tests/test_parser.py b/tests/test_parser.py
index 0053e932..aa96b592 100644
--- a/tests/test_parser.py
+++ b/tests/test_parser.py
@@ -243,7 +243,7 @@ class ParserMissingArcDescriptionTest(CoverageTest):
     def test_missing_arc_descriptions_for_small_callables(self):
         # We use 2.7 features here, so just skip this test on 2.6
         if env.PYVERSION < (2, 7):
-            self.skipTest("No dict or set comps in 2.6")        # pragma: not covered
+            self.skipTest("No dict or set comps in 2.6")
 
         parser = self.parse_text(u"""\
             callables = [
diff --git a/tests/test_process.py b/tests/test_process.py
index 4a52a946..666d3cc4 100644
--- a/tests/test_process.py
+++ b/tests/test_process.py
@@ -581,7 +581,7 @@ class ProcessTest(CoverageTest):
         self.assertEqual(infos[0]['note'], u"These are musical notes: ♫𝅗𝅥♩")
 
     @pytest.mark.expensive
-    def test_fullcoverage(self):                        # pragma: not covered
+    def test_fullcoverage(self):                        # pragma: no metacov
         if env.PY2:             # This doesn't work on Python 2.
             self.skipTest("fullcoverage doesn't work on Python 2.")
         # It only works with the C tracer, and if we aren't measuring ourselves.
@@ -1193,13 +1193,13 @@ def find_writable_pth_directory():
         with open(try_it, "w") as f:
             try:
                 f.write("foo")
-            except (IOError, OSError):              # pragma: not covered
+            except (IOError, OSError):              # pragma: cant happen
                 continue
 
         os.remove(try_it)
         return pth_dir
 
-    return None
+    return None                                     # pragma: cant happen
 
 WORKER = os.environ.get('PYTEST_XDIST_WORKER', '')
 PTH_DIR = find_writable_pth_directory()
@@ -1241,7 +1241,7 @@ class ProcessStartupTest(ProcessCoverageMixin, CoverageTest):
             f.close()
             """)
 
-    def test_subprocess_with_pth_files(self):           # pragma: not covered
+    def test_subprocess_with_pth_files(self):           # pragma: no metacov
         if env.METACOV:
             self.skipTest("Can't test sub-process pth file suppport during metacoverage")
 
@@ -1268,7 +1268,7 @@ class ProcessStartupTest(ProcessCoverageMixin, CoverageTest):
         data.read_file(".mycovdata")
         self.assertEqual(data.line_counts()['sub.py'], 3)
 
-    def test_subprocess_with_pth_files_and_parallel(self):  # pragma: not covered
+    def test_subprocess_with_pth_files_and_parallel(self):  # pragma: no metacov
         # https://bitbucket.org/ned/coveragepy/issues/492/subprocess-coverage-strange-detection-of
         if env.METACOV:
             self.skipTest("Can't test sub-process pth file suppport during metacoverage")
@@ -1315,7 +1315,7 @@ class ProcessStartupWithSourceTest(ProcessCoverageMixin, CoverageTest):
 
     def assert_pth_and_source_work_together(
         self, dashm, package, source
-    ):                                                  # pragma: not covered
+    ):                                                  # pragma: no metacov
         """Run the test for a particular combination of factors.
 
         The arguments are all strings: