Issue #4050: inspect.findsource/getsource now raise an IOError if the 'source'
file is a binary.  Patch by Brodie Rao, test by Daniel Diniz.
diff --git a/Lib/test/test_inspect.py b/Lib/test/test_inspect.py
index 7312cac..5c41433 100644
--- a/Lib/test/test_inspect.py
+++ b/Lib/test/test_inspect.py
@@ -9,6 +9,9 @@
 from test import inspect_fodder as mod
 from test import inspect_fodder2 as mod2
 
+# C module for test_findsource_binary
+import time
+
 # Functions tested in this suite:
 # ismodule, isclass, ismethod, isfunction, istraceback, isframe, iscode,
 # isbuiltin, isroutine, isgenerator, isgeneratorfunction, getmembers,
@@ -329,6 +332,10 @@
     def test_method_in_dynamic_class(self):
         self.assertSourceEqual(mod2.method_in_dynamic_class, 95, 97)
 
+    def test_findsource_binary(self):
+        self.assertRaises(IOError, inspect.getsource, time)
+        self.assertRaises(IOError, inspect.findsource, time)
+
 # Helper for testing classify_class_attrs.
 def attrs_wo_objs(cls):
     return [t[:3] for t in inspect.classify_class_attrs(cls)]