1 files changed, 71 insertions, 4 deletions
diff --git a/Lib/test/test_contextlib.py b/Lib/test/test_contextlib.py
index 9e45f70..e8d504d 100644
--- a/Lib/test/test_contextlib.py
+++ b/Lib/test/test_contextlib.py
@@ -1,5 +1,6 @@
 """Unit tests for contextlib.py, and other context managers."""
 
+import io
 import sys
 import tempfile
 import unittest
@@ -631,10 +632,76 @@ class TestExitStack(unittest.TestCase):
         stack.push(cm)
         self.assertIs(stack._exit_callbacks[-1], cm)
 
+class TestRedirectStdout(unittest.TestCase):
+
+    def test_redirect_to_string_io(self):
+        f = io.StringIO()
+        with redirect_stdout(f):
+            help(pow)
+        s = f.getvalue()
+        self.assertIn('pow', s)
+
+    def test_enter_result_is_target(self):
+        f = io.StringIO()
+        with redirect_stdout(f) as enter_result:
+            self.assertIs(enter_result, f)
+
+    def test_cm_is_reusable(self):
+        f = io.StringIO()
+        write_to_f = redirect_stdout(f)
+        with write_to_f:
+            print("Hello", end=" ")
+        with write_to_f:
+            print("World!")
+        s = f.getvalue()
+        self.assertEqual(s, "Hello World!\n")
+
+    # If this is ever made reentrant, update the reusable-but-not-reentrant
+    # example at the end of the contextlib docs accordingly.
+    def test_nested_reentry_fails(self):
+        f = io.StringIO()
+        write_to_f = redirect_stdout(f)
+        with self.assertRaisesRegex(RuntimeError, "Cannot reenter"):
+            with write_to_f:
+                print("Hello", end=" ")
+                with write_to_f:
+                    print("World!")
+
+
+class TestSuppress(unittest.TestCase):
+
+    def test_no_result_from_enter(self):
+        with suppress(ValueError) as enter_result:
+            self.assertIsNone(enter_result)
+
+    def test_no_exception(self):
+        with suppress(ValueError):
+            self.assertEqual(pow(2, 5), 32)
+
+    def test_exact_exception(self):
+        with suppress(TypeError):
+            len(5)
+
+    def test_multiple_exception_args(self):
+        with suppress(ZeroDivisionError, TypeError):
+            1/0
+        with suppress(ZeroDivisionError, TypeError):
+            len(5)
+
+    def test_exception_hierarchy(self):
+        with suppress(LookupError):
+            'Hello'[50]
 
-# This is needed to make the test actually run under regrtest.py!
-def test_main():
-    support.run_unittest(__name__)
+    def test_cm_is_reentrant(self):
+        ignore_exceptions = suppress(Exception)
+        with ignore_exceptions:
+            pass
+        with ignore_exceptions:
+            len(5)
+        with ignore_exceptions:
+            1/0
+            with ignore_exceptions: # Check nested usage
+                len(5)
 
 if __name__ == "__main__":
-    test_main()
+    unittest.main()