Implement most of @nedbat's feedback

coverage/cmdline.py

@@ -25,8 +25,9 @@
 from coverage.control import DEFAULT_DATAFILE
 from coverage.data import combinable_files, debug_data_file
 from coverage.debug import info_header, short_stack, write_formatted_info
-from coverage.exceptions import _BaseCoverageException, _ExceptionDuringRun, NoSource, \
-    NoDataFilesFoundError
+from coverage.exceptions import (
+    _BaseCoverageException, _ExceptionDuringRun, NoSource, NoDataFilesFoundError,
+)
 from coverage.execfile import PyRunner
 from coverage.results import display_covered, should_fail_under
 from coverage.version import __url__

coverage/data.py

@@ -82,7 +82,7 @@ def combinable_files(data_file: str, data_paths: Iterable[str] | None = None) ->
             pattern = glob.escape(os.path.join(os.path.abspath(p), local)) +".*"
             files_to_combine.extend(glob.glob(pattern))
         else:
-            raise DataFileOrDirectoryNotFoundError.new_for_data_file_or_directory(
+            raise DataFileOrDirectoryNotFoundError.new(
                 p, is_combining=True
             )
 
@@ -91,7 +91,7 @@ def combinable_files(data_file: str, data_paths: Iterable[str] | None = None) ->
     files_to_combine = [fnm for fnm in files_to_combine if not fnm.endswith("-journal")]
 
     if not files_to_combine:
-        raise NoDataFilesFoundError.new_for_data_directory(data_dir)
+        raise NoDataFilesFoundError.new(data_dir)
 
     # Sorting isn't usually needed, since it shouldn't matter what order files
     # are combined, but sorting makes tests more predictable, and makes
@@ -197,7 +197,7 @@ def combine_parallel_data(
             file_be_gone(f)
 
     if strict and not combined_any:
-        raise UnusableDataFilesError.new_for_data_files(*files_to_combine)
+        raise UnusableDataFilesError.new(*files_to_combine)
 
 
 def debug_data_file(filename: str) -> None:

coverage/exceptions.py

@@ -11,7 +11,7 @@
 def _message_append_combine_hint(message: str, is_combining: bool) -> str:
     """Append information about the combine command to error messages."""
     if not is_combining:
-        message += " Perhaps `coverage combine` must be run first."
+        message += " Perhaps 'coverage combine' must be run first."
     return message
 
 
@@ -43,48 +43,48 @@ class NoDataError(CoverageException):
 class DataFileOrDirectoryNotFoundError(NoDataError):
     """A data file or data directory could be found."""
     @classmethod
-    def new_for_data_file_or_directory(
+    def new(
         cls, data_file_or_directory_path: str, *, is_combining: bool = False
-    ) -> 'DataFileOrDirectoryNotFoundError':
+    ) -> DataFileOrDirectoryNotFoundError:
         """
         Create a new instance.
         """
         message = (
-            f"The data file or directory `{os.path.abspath(data_file_or_directory_path)}` could not"
-            " be found."
+            f"The data file or directory '{os.path.abspath(data_file_or_directory_path)}' could not"
+            + " be found."
         )
         return cls(_message_append_combine_hint(message, is_combining))
 
 
 class NoDataFilesFoundError(NoDataError):
     """No data files could be found in a data directory."""
     @classmethod
-    def new_for_data_directory(
+    def new(
         cls, data_directory_path: str, *, is_combining: bool = False
     ) -> 'NoDataFilesFoundError':
         """
         Create a new instance.
         """
         message = (
-            f"The data directory `{os.path.abspath(data_directory_path)}` does not contain any data"
-            " files."
+            f"The data directory '{os.path.abspath(data_directory_path)}' does not contain any data"
+            + " files."
         )
         return cls(_message_append_combine_hint(message, is_combining))
 
 
 class UnusableDataFilesError(NoDataError):
     """The given data files are unusable."""
     @classmethod
-    def new_for_data_files(cls, *data_file_paths: str) -> 'UnusableDataFilesError':
+    def new(cls, *data_file_paths: str) -> 'UnusableDataFilesError':
         """
         Create a new instance.
         """
         message = (
             "The following data files are unusable, perhaps because they do not contain valid"
-            " coverage information:"
+            + " coverage information:"
         )
         for data_file_path in data_file_paths:
-            message += f"\n- `{os.path.abspath(data_file_path)}`"
+            message += f"\n- '{os.path.abspath(data_file_path)}'"
 
         return cls(message)
 

coverage/html.py

@@ -317,7 +317,7 @@ def report(self, morfs: Iterable[TMorf] | None) -> float:
                 file_be_gone(os.path.join(self.directory, ftr.html_filename))
 
         if not have_data:
-            raise DataFileOrDirectoryNotFoundError.new_for_data_file_or_directory(
+            raise DataFileOrDirectoryNotFoundError.new(
                 os.path.dirname(self.coverage.get_data().base_filename())
             )
 

coverage/report.py

@@ -183,7 +183,7 @@ def report(self, morfs: Iterable[TMorf] | None, outfile: IO[str] | None = None)
             self.report_one_file(fr, analysis)
 
         if not self.total.n_files and not self.skipped_count:
-            raise DataFileOrDirectoryNotFoundError.new_for_data_file_or_directory(
+            raise DataFileOrDirectoryNotFoundError.new(
                 os.path.dirname(self.coverage.get_data().base_filename())
             )
 

coverage/report_core.py

@@ -94,7 +94,7 @@ def get_analysis_to_report(
         fr_morfs = [(fr, morf) for (fr, morf) in fr_morfs if not matcher.match(fr.filename)]
 
     if not fr_morfs:
-        raise DataFileOrDirectoryNotFoundError.new_for_data_file_or_directory(
+        raise DataFileOrDirectoryNotFoundError.new(
             os.path.dirname(coverage.get_data().base_filename())
         )
 

tests/test_api.py

@@ -303,8 +303,8 @@ def test_empty_reporting(self) -> None:
         with pytest.raises(
             NoDataError,
             match=(
-                r"^The data file or directory `(.+?)` could not be found\. Perhaps `coverage "
-                r"combine` must be run first\.$"
+                r"^The data file or directory '(.+?)' could not be found\. Perhaps 'coverage "
+                r"combine' must be run first\.$"
             )
         ):
             cov.report()
@@ -455,8 +455,8 @@ def test_combining_twice(self) -> None:
         with pytest.raises(
             NoDataError,
             match=(
-                r"^The data directory `(.+?)` does not contain any data files. Perhaps `coverage "
-                r"combine` must be run first.$"
+                r"^The data directory '(.+?)' does not contain any data files. Perhaps 'coverage "
+                r"combine' must be run first.$"
             )
         ):
             cov2.combine(strict=True, keep=False)
@@ -1392,7 +1392,7 @@ def test_combine_no_usable_files(self) -> None:
                 NoDataError,
                 match=(
                     r"^The following data files are unusable, perhaps because they do not contain "
-                    r"valid coverage information:\n- `(.+?)`\n- `(.+?)`$"
+                    r"valid coverage information:\n- '(.+?)'\n- '(.+?)'$"
                 )
             ):
                 cov.combine(strict=True)

tests/test_coverage.py

@@ -1638,8 +1638,8 @@ def test_no_data_to_report_on_annotate(self) -> None:
         with pytest.raises(
             NoDataError,
             match=(
-                r"^The data file or directory `(.+?)` could not be found\. Perhaps `coverage "
-                r"combine` must be run first\.$"
+                r"^The data file or directory '(.+?)' could not be found\. Perhaps 'coverage "
+                r"combine' must be run first\.$"
             )
         ):
             self.command_line("annotate -d ann")
@@ -1651,8 +1651,8 @@ def test_no_data_to_report_on_html(self) -> None:
         with pytest.raises(
             NoDataError,
             match=(
-                r"^The data file or directory `(.+?)` could not be found\. Perhaps `coverage "
-                r"combine` must be run first\.$"
+                r"^The data file or directory '(.+?)' could not be found\. Perhaps 'coverage "
+                r"combine' must be run first\.$"
             )
         ):
             self.command_line("html -d htmlcov")
@@ -1663,8 +1663,8 @@ def test_no_data_to_report_on_xml(self) -> None:
         with pytest.raises(
             NoDataError,
             match=(
-                r"^The data file or directory `(.+?)` could not be found\. Perhaps `coverage "
-                r"combine` must be run first\.$"
+                r"^The data file or directory '(.+?)' could not be found\. Perhaps 'coverage "
+                r"combine' must be run first\.$"
             )
         ):
             self.command_line("xml")

tests/test_data.py

@@ -915,7 +915,7 @@ def test_combining_from_files(self) -> None:
 
     def test_combining_from_nonexistent_directories(self) -> None:
         covdata = DebugCoverageData()
-        msg = r"^The data file or directory `(.+?)` could not be found.$"
+        msg = r"^The data file or directory '(.+?)' could not be found.$"
         with pytest.raises(NoDataError, match=msg):
             combine_parallel_data(covdata, data_paths=['xyzzy'])
 

tests/test_html.py

@@ -429,8 +429,8 @@ def test_dothtml_not_python(self) -> None:
         with pytest.raises(
             NoDataError,
             match=(
-                r"^The data file or directory `(.+?)` could not be found\. Perhaps `coverage "
-                r"combine` must be run first\.$"
+                r"^The data file or directory '(.+?)' could not be found\. Perhaps 'coverage "
+                r"combine' must be run first\.$"
             )
         ):
             cov.html_report()

tests/test_process.py

@@ -1145,8 +1145,8 @@ def test_report(self) -> None:
         st, out = self.run_command_status("coverage report")
         assert re.match(
             (
-                r"The data file or directory `([^`]+?)` could not be found\. Perhaps `coverage "
-                r"combine` must be run first\."
+                r"The data file or directory '([^']+?)' could not be found\. Perhaps 'coverage "
+                + r"combine' must be run first\."
             ),
             out
         )

tests/test_report.py

@@ -554,8 +554,8 @@ def test_report_skip_covered_no_data(self) -> None:
         with pytest.raises(
             NoDataError,
             match=(
-                r"^The data file or directory `(.+?)` could not be found\. Perhaps `coverage "
-                r"combine` must be run first\.$"
+                r"^The data file or directory '(.+?)' could not be found\. Perhaps 'coverage "
+                r"combine' must be run first\.$"
             )
         ):
             self.get_report(cov, skip_covered=True)
@@ -753,8 +753,8 @@ def test_dotpy_not_python_ignored(self) -> None:
         with pytest.raises(
             NoDataError,
             match=(
-                r"^The data file or directory `(.+?)` could not be found\. Perhaps `coverage "
-                r"combine` must be run first\.$"
+                r"^The data file or directory '(.+?)' could not be found\. Perhaps 'coverage "
+                r"combine' must be run first\.$"
             )
         ):
             with pytest.warns(Warning) as warns:
@@ -776,8 +776,8 @@ def test_dothtml_not_python(self) -> None:
         with pytest.raises(
             NoDataError,
             match=(
-                r"^The data file or directory `(.+?)` could not be found\. Perhaps `coverage "
-                r"combine` must be run first\.$"
+                r"^The data file or directory '(.+?)' could not be found\. Perhaps 'coverage "
+                r"combine' must be run first\.$"
             )
         ):
             self.get_report(cov, morfs=["mycode.html"])

tests/test_xml.py

@@ -148,8 +148,8 @@ def test_no_data(self) -> None:
         with pytest.raises(
             NoDataError,
             match=(
-                r"^The data file or directory `(.+?)` could not be found\. Perhaps `coverage "
-                r"combine` must be run first\.$"
+                r"^The data file or directory '(.+?)' could not be found\. Perhaps 'coverage "
+                r"combine' must be run first\.$"
             )
         ):
             self.run_xml_report()