Temporary commit of fix to issue #5380 (in order to watch buildbot response)

Lib/test/test_io.py

@@ -2394,6 +2394,47 @@ class MiscIOTest(unittest.TestCase):
         # baseline "io" module.
         self._check_abc_inheritance(io)
 
+    # Issue #5380: reading all available bytes from a pipe or a PTY when
+    # the other end has been closed.
+
+    def check_pipe_func(self, pipe_func, buffered):
+        master_fd, slave_fd = pipe_func()
+        # Simulate a subprocess writing some data to the
+        # slave end of the pipe, and then exiting.
+        data = b'TEST DATA'
+        try:
+            os.write(slave_fd, data)
+        finally:
+            os.close(slave_fd)
+        with self.open(master_fd, "rb", buffering=-1 if buffered else 0) as f:
+            # Request more data than available
+            gotdata = f.read(len(data) + 1)
+            self.assertEqual(gotdata, data)
+            # Trying to read again returns an empty string
+            self.assertEqual(b'', f.read())
+            self.assertEqual(b'', f.read(1))
+
+    def test_pipe_read_buffered(self):
+        if not hasattr(os, 'pipe'):
+            self.skipTest("os.pipe not available")
+        self.check_pipe_func(os.pipe, True)
+
+    def test_pipe_read_raw(self):
+        if not hasattr(os, 'pipe'):
+            self.skipTest("os.pipe not available")
+        self.check_pipe_func(os.pipe, False)
+
+    def test_openpty_read_buffered(self):
+        if not hasattr(os, 'openpty'):
+            self.skipTest("os.openpty not available")
+        self.check_pipe_func(os.openpty, True)
+
+    def test_openpty_read_raw(self):
+        if not hasattr(os, 'openpty'):
+            self.skipTest("os.openpty not available")
+        self.check_pipe_func(os.openpty, False)
+
+
 class CMiscIOTest(MiscIOTest):
     io = io