Issue #10963: Ensure that subprocess.communicate() never raises EPIPE.
diff --git a/Lib/test/test_subprocess.py b/Lib/test/test_subprocess.py
index 04eb9b1..b635ef3 100644
--- a/Lib/test/test_subprocess.py
+++ b/Lib/test/test_subprocess.py
@@ -597,6 +597,24 @@
         self.assertFalse(os.path.exists(ofname))
         self.assertFalse(os.path.exists(efname))
 
+    def test_communicate_epipe(self):
+        # Issue 10963: communicate() should hide EPIPE
+        p = subprocess.Popen([sys.executable, "-c", 'pass'],
+                             stdin=subprocess.PIPE,
+                             stdout=subprocess.PIPE,
+                             stderr=subprocess.PIPE)
+        self.addCleanup(p.stdout.close)
+        self.addCleanup(p.stderr.close)
+        self.addCleanup(p.stdin.close)
+        p.communicate("x" * 2**20)
+
+    def test_communicate_epipe_only_stdin(self):
+        # Issue 10963: communicate() should hide EPIPE
+        p = subprocess.Popen([sys.executable, "-c", 'pass'],
+                             stdin=subprocess.PIPE)
+        self.addCleanup(p.stdin.close)
+        time.sleep(2)
+        p.communicate("x" * 2**20)
 
 # context manager
 class _SuppressCoreFiles(object):