feat: added support for finding unexecuted namespace packages (#1387)

* add support for namespace packages

* fixed typo

* update documentation

* fixed lint issues

* changed versionadded

* convert to config setting

* removed pure formatting changes

* code review changes

Co-authored-by: Ned Batchelder <ned@nedbatchelder.com>

7 files changed, 41 insertions, 5 deletions

diff --git a/coverage/config.py b/coverage/config.py
index 7b765edf..994154f6 100644
--- a/coverage/config.py
+++ b/coverage/config.py
@@ -200,6 +200,7 @@ class CoverageConfig:
         self.fail_under = 0.0
         self.format = None
         self.ignore_errors = False
+        self.include_namespace_packages = False
         self.report_include = None
         self.report_omit = None
         self.partial_always_list = DEFAULT_PARTIAL_ALWAYS[:]
@@ -375,6 +376,7 @@ class CoverageConfig:
         ('fail_under', 'report:fail_under', 'float'),
         ('format', 'report:format', 'boolean'),
         ('ignore_errors', 'report:ignore_errors', 'boolean'),
+        ('include_namespace_packages', 'report:include_namespace_packages', 'boolean'),
         ('partial_always_list', 'report:partial_branches_always', 'regexlist'),
         ('partial_list', 'report:partial_branches', 'regexlist'),
         ('precision', 'report:precision', 'int'),
diff --git a/coverage/control.py b/coverage/control.py
index 91ad5a78..a955c283 100644
--- a/coverage/control.py
+++ b/coverage/control.py
@@ -530,6 +530,7 @@ class Coverage:
         self._inorout = InOrOut(
             warn=self._warn,
             debug=(self._debug if self._debug.should('trace') else None),
+            include_namespace_packages=self.config.include_namespace_packages
         )
         self._inorout.configure(self.config)
         self._inorout.plugins = self._plugins
diff --git a/coverage/files.py b/coverage/files.py
index bfd808ff..8be292f3 100644
--- a/coverage/files.py
+++ b/coverage/files.py
@@ -461,7 +461,7 @@ class PathAliases:
         return path
 
 
-def find_python_files(dirname):
+def find_python_files(dirname, include_namespace_packages):
     """Yield all of the importable Python files in `dirname`, recursively.
 
     To be importable, the files have to be in a directory with a __init__.py,
@@ -472,7 +472,8 @@ def find_python_files(dirname):
 
     """
     for i, (dirpath, dirnames, filenames) in enumerate(os.walk(dirname)):
-        if i > 0 and '__init__.py' not in filenames:
+        if (i > 0 and '__init__.py' not in filenames
+            and not include_namespace_packages):
             # If a directory doesn't have __init__.py, then it isn't
             # importable and neither are its files
             del dirnames[:]
diff --git a/coverage/inorout.py b/coverage/inorout.py
index 2e534c85..0d3f6d67 100644
--- a/coverage/inorout.py
+++ b/coverage/inorout.py
@@ -189,9 +189,10 @@ def add_coverage_paths(paths):
 class InOrOut:
     """Machinery for determining what files to measure."""
 
-    def __init__(self, warn, debug):
+    def __init__(self, warn, debug, include_namespace_packages):
         self.warn = warn
         self.debug = debug
+        self.include_namespace_packages = include_namespace_packages
 
         # The matchers for should_trace.
         self.source_match = None
@@ -565,7 +566,10 @@ class InOrOut:
         Yield the file path, and the plugin name that handles the file.
 
         """
-        py_files = ((py_file, None) for py_file in find_python_files(src_dir))
+        py_files = (
+            (py_file, None) for py_file in
+            find_python_files(src_dir, self.include_namespace_packages)
+        )
         plugin_files = self._find_plugin_files(src_dir)
 
         for file_path, plugin_name in itertools.chain(py_files, plugin_files):
diff --git a/doc/config.rst b/doc/config.rst
index 83f64a4d..b5112982 100644
--- a/doc/config.rst
+++ b/doc/config.rst
@@ -410,6 +410,14 @@ warning instead of an exception.
 See :ref:`source` for details.
 
 
+.. _config_include_namespace_packages:
+
+[report] include_namespace_packages
+...................................
+
+(boolean, default False) Include folders without an ``__init__.py`` in the
+coverage.
+
 .. _config_report_omit:
 
 [report] omit
diff --git a/tests/test_config.py b/tests/test_config.py
index 444719fd..5f8a0547 100644
--- a/tests/test_config.py
+++ b/tests/test_config.py
@@ -494,6 +494,8 @@ class ConfigFileTest(UsingModulesMixin, CoverageTest):
         skip_covered = TruE
         skip_empty  =TruE
 
+        include_namespace_packages = TRUE
+
         [{section}html]
 
         directory    =     c:\\tricky\\dir.somewhere
@@ -589,6 +591,7 @@ class ConfigFileTest(UsingModulesMixin, CoverageTest):
         assert cov.config.get_plugin_options("plugins.another") == {}
         assert cov.config.json_show_contexts is True
         assert cov.config.json_pretty_print is True
+        assert cov.config.include_namespace_packages is True
 
     def test_config_file_settings(self):
         self.make_file(".coveragerc", self.LOTSA_SETTINGS.format(section=""))
diff --git a/tests/test_files.py b/tests/test_files.py
index 561b961d..a69d1a4b 100644
--- a/tests/test_files.py
+++ b/tests/test_files.py
@@ -585,13 +585,30 @@ class FindPythonFilesTest(CoverageTest):
         self.make_file("sub/ssub/~s.py")            # nope: editor effluvia
         self.make_file("sub/lab/exp.py")            # nope: no __init__.py
         self.make_file("sub/windows.pyw")
-        py_files = set(find_python_files("sub"))
+        py_files = set(find_python_files("sub", include_namespace_packages=False))
         self.assert_same_files(py_files, [
             "sub/a.py", "sub/b.py",
             "sub/ssub/__init__.py", "sub/ssub/s.py",
             "sub/windows.pyw",
         ])
 
+    def test_find_python_files_include_namespace_packages(self):
+        self.make_file("sub/a.py")
+        self.make_file("sub/b.py")
+        self.make_file("sub/x.c")                   # nope: not .py
+        self.make_file("sub/ssub/__init__.py")
+        self.make_file("sub/ssub/s.py")
+        self.make_file("sub/ssub/~s.py")            # nope: editor effluvia
+        self.make_file("sub/lab/exp.py")
+        self.make_file("sub/windows.pyw")
+        py_files = set(find_python_files("sub", include_namespace_packages=True))
+        self.assert_same_files(py_files, [
+            "sub/a.py", "sub/b.py",
+            "sub/ssub/__init__.py", "sub/ssub/s.py",
+            "sub/lab/exp.py",
+            "sub/windows.pyw",
+        ])
+
 
 @pytest.mark.skipif(not env.WINDOWS, reason="Only need to run Windows tests on Windows.")
 class WindowsFileTest(CoverageTest):