diff -r 67dc99a989cd Lib/doctest.py
--- a/Lib/doctest.py	Mon Jun 25 20:57:36 2012 -0700
+++ b/Lib/doctest.py	Tue Jun 26 08:15:01 2012 +0200
@@ -2766,20 +2766,26 @@
             name, _ = os.path.splitext(name)
         print("usage: {0} [-v] file ...".format(name))
         return 2
+    failures = False
     for filename in testfiles:
-        if filename.endswith(".py"):
-            # It is a module -- insert its dir into sys.path and try to
-            # import it. If it is part of a package, that possibly
-            # won't work because of package imports.
-            dirname, filename = os.path.split(filename)
-            sys.path.insert(0, dirname)
-            m = __import__(filename[:-3])
-            del sys.path[0]
-            failures, _ = testmod(m)
-        else:
-            failures, _ = testfile(filename, module_relative=False)
-        if failures:
-            return 1
+        try:
+            if filename.endswith(".py"):
+                # It is a module -- insert its dir into sys.path and try to
+                # import it. If it is part of a package, that possibly
+                # won't work because of package imports.
+                dirname, filename = os.path.split(filename)
+                sys.path.insert(0, dirname)
+                m = __import__(filename[:-3])
+                del sys.path[0]
+                failure, _ = testmod(m)
+            else:
+                failure, _ = testfile(filename, module_relative=False)
+            failures |= failure
+        except IOError as e:
+            print "Cannot read '{0}': {1}".format(filename, e)
+            failures = True
+    if failures:
+        return 1
     return 0