When finding the source for a frame, really check if it exists

3 files changed, 25 insertions, 13 deletions

diff --git a/coverage/control.py b/coverage/control.py
index 63c9d382..1044fad0 100644
--- a/coverage/control.py
+++ b/coverage/control.py
@@ -308,11 +308,18 @@ class Coverage(object):
 
     def _source_for_file(self, filename):
         """Return the source file for `filename`."""
-        if not filename.endswith(".py"):
-            if filename[-4:-1] == ".py":
-                filename = filename[:-1]
-            elif filename.endswith("$py.class"):    # jython
-                filename = filename[:-9] + ".py"
+        if filename.endswith(".py"):
+            return filename
+        elif filename.endswith((".pyc", ".pyo")):
+            try_filename = filename[:-1]
+            if os.path.exists(try_filename):
+                return try_filename
+            if sys.platform == "win32":
+                try_filename += "w"
+                if os.path.exists(try_filename):
+                    return try_filename
+        elif filename.endswith("$py.class"):    # Jython
+            filename = filename[:-9] + ".py"
         return filename
 
     def _name_for_module(self, module_globals, filename):
diff --git a/tests/test_codeunit.py b/tests/test_codeunit.py
index 1a064fca..ea65d85f 100644
--- a/tests/test_codeunit.py
+++ b/tests/test_codeunit.py
@@ -12,6 +12,11 @@ from tests.coveragetest import CoverageTest
 # Unable to import 'aa' (No module named aa)
 
 
+def native(filename):
+    """Make `filename` into a native form."""
+    return filename.replace("/", os.sep)
+
+
 class CodeUnitTest(CoverageTest):
     """Tests for coverage.codeunit"""
 
@@ -59,9 +64,9 @@ class CodeUnitTest(CoverageTest):
         acu = PythonCodeUnit(aa)
         bcu = PythonCodeUnit(aa.bb)
         ccu = PythonCodeUnit(aa.bb.cc)
-        self.assertEqual(acu.name, "aa.py")
-        self.assertEqual(bcu.name, "aa/bb.py")
-        self.assertEqual(ccu.name, "aa/bb/cc.py")
+        self.assertEqual(acu.name, native("aa.py"))
+        self.assertEqual(bcu.name, native("aa/bb.py"))
+        self.assertEqual(ccu.name, native("aa/bb/cc.py"))
         self.assertEqual(acu.flat_rootname(), "aa_py")
         self.assertEqual(bcu.flat_rootname(), "aa_bb_py")
         self.assertEqual(ccu.flat_rootname(), "aa_bb_cc_py")
@@ -77,9 +82,9 @@ class CodeUnitTest(CoverageTest):
         acu = PythonCodeUnit(aa.afile)
         bcu = PythonCodeUnit(aa.bb.bfile)
         ccu = PythonCodeUnit(aa.bb.cc.cfile)
-        self.assertEqual(acu.name, "aa/afile.py")
-        self.assertEqual(bcu.name, "aa/bb/bfile.py")
-        self.assertEqual(ccu.name, "aa/bb/cc/cfile.py")
+        self.assertEqual(acu.name, native("aa/afile.py"))
+        self.assertEqual(bcu.name, native("aa/bb/bfile.py"))
+        self.assertEqual(ccu.name, native("aa/bb/cc/cfile.py"))
         self.assertEqual(acu.flat_rootname(), "aa_afile_py")
         self.assertEqual(bcu.flat_rootname(), "aa_bb_bfile_py")
         self.assertEqual(ccu.flat_rootname(), "aa_bb_cc_cfile_py")
diff --git a/tests/test_summary.py b/tests/test_summary.py
index 8c9cf6d7..fa5b4461 100644
--- a/tests/test_summary.py
+++ b/tests/test_summary.py
@@ -435,8 +435,8 @@ class SummaryTest(CoverageTest):
             report = self.get_report(cov)
             self.assertNotIn("NoSource", report)
             report = report.splitlines()
-            self.assertIn("start 2 0 100%", report)
-            self.assertIn("mod 1 0 100%", report)
+            self.assertIn("start.pyw 2 0 100%", report)
+            self.assertIn("mod.pyw 1 0 100%", report)
 
 
 class SummaryTest2(CoverageTest):