1 files changed, 37 insertions, 0 deletions
diff --git a/tests/test_misc.py b/tests/test_misc.py
index d5a707c..e439240 100755
--- a/tests/test_misc.py
+++ b/tests/test_misc.py
@@ -24,6 +24,7 @@ import re
 import signal
 import time
 import tempfile
+import threading
 import os
 
 import pexpect
@@ -41,6 +42,42 @@ else:
         return s
 
 
+class DiscardOutput(threading.Thread):
+    def __init__(self, child):
+        self.child = child
+        threading.Thread.__init__(self)
+
+    def run(self):
+        # discard all output, expecting to program exit
+        self.child.expect(pexpect.EOF)
+
+
+class TestCaseBlockingWrite(PexpectTestCase.PexpectTestCase):
+    BASH_SCRIPT=('n=0; while [ $n -lt 10000 ]; do echo $n; '
+                 'let n="$n + 1"; done; echo END > {0}; exit')
+
+    def test_discard_output_using_background_thread(self):
+        " Test that a background thread can discard output."
+        # this is slightly contrary to the recommendation in commonissues.rst
+        # of section "Threads" regarding whether a background thread can read
+        # from a file descriptor created in a main thread -- presumably only
+        # an issue in RHEL 8. This test case matches the first recommendation
+        # of section, "Blocking Child" of the same document.
+        bash = pexpect.spawn('bash', echo=False)
+        result_file = tempfile.mktemp()
+        try:
+            bash.sendline(self.BASH_SCRIPT.format(result_file))
+            bash.expect(re.compile('\s100\s'), timeout=2)
+            thread = DiscardOutput(bash)
+            thread.start()
+            thread.join()
+            assert os.path.exists(result_file)
+            assert open(result_file).read().strip() == 'END'
+        finally:
+            if os.path.exists(result_file):
+                os.unlink(result_file)
+
+
 class TestCaseMisc(PexpectTestCase.PexpectTestCase):
 
     def test_isatty(self):