Some prep work for finding completely uncovered files.

2 files changed, 18 insertions, 1 deletions

diff --git a/coverage/data.py b/coverage/data.py
index fe076bef..6d49f710 100644
--- a/coverage/data.py
+++ b/coverage/data.py
@@ -52,7 +52,10 @@ class CoverageData(object):
         # A map from canonical Python source file name to a dictionary with an
         # entry for each pair of line numbers forming an arc:
         #
-        # { filename: { (l1,l2): None, ... }, ...}
+        #   {
+        #       'filename1.py': { (12,14): None, (47,48): None, ... },
+        #       ...
+        #       }
         #
         self.arcs = {}
 
diff --git a/coverage/files.py b/coverage/files.py
index 741b456f..9a8ac564 100644
--- a/coverage/files.py
+++ b/coverage/files.py
@@ -102,6 +102,7 @@ class TreeMatcher(object):
                     return True
         return False
 
+
 class FnmatchMatcher(object):
     """A matcher for files by filename pattern."""
     def __init__(self, pats):
@@ -116,3 +117,16 @@ class FnmatchMatcher(object):
             if fnmatch.fnmatch(fpath, pat):
                 return True
         return False
+
+
+def find_python_files(dirname):
+    """Yield all of the importable Python files in `dirname`, recursively."""
+    for dirpath, dirnames, filenames in os.walk(dirname, topdown=True):
+        if '__init__.py' not in filenames:
+            # If a directory doesn't have __init__.py, then it isn't
+            # importable and neither are its files
+            del dirnames[:]
+            continue
+        for filename in filenames:
+            if fnmatch.fnmatch(filename, "*.py"):
+                yield os.path.join(dirpath, filename)