optimize pty buffering and searching

Python strings are slow and expensive as buffers because they're
immutable; replace the output buffer with a StringIO/BytesIO
object

see: https://github.com/pexpect/pexpect/issues/438

2 files changed, 14 insertions, 0 deletions

diff --git a/tests/test_expect.py b/tests/test_expect.py
index dcf059b..ec55d43 100755
--- a/tests/test_expect.py
+++ b/tests/test_expect.py
@@ -400,6 +400,14 @@ class ExpectTestCase (PexpectTestCase.PexpectTestCase):
         else:
             self.fail ('Expected an EOF exception.')
 
+    def test_buffer_interface(self):
+        p = pexpect.spawn('cat', timeout=5)
+        p.sendline (b'Hello')
+        p.expect (b'Hello')
+        assert len(p.buffer)
+        p.buffer = b'Testing'
+        p.sendeof ()
+
     def _before_after(self, p):
         p.timeout = 5
 
diff --git a/tests/test_performance.py b/tests/test_performance.py
index 7be0cf6..63778af 100755
--- a/tests/test_performance.py
+++ b/tests/test_performance.py
@@ -23,6 +23,7 @@ from __future__ import print_function
 import unittest, time, sys
 import platform
 import pexpect
+import re
 from . import PexpectTestCase
 
 # This isn't exactly a unit test, but it fits in nicely with the rest of the tests.
@@ -101,6 +102,11 @@ class PerformanceTestCase (PexpectTestCase.PexpectTestCase):
         self.faster_range(100000)
         print("100000 calls to faster_range:", (time.time() - start_time))
 
+    def test_large_stdout_stream(self):
+        e = pexpect.spawn('openssl rand -base64 {}'.format(1024*1024*25), searchwindowsize=1000)
+        resp = e.expect(['Password:', pexpect.EOF, pexpect.TIMEOUT])
+        assert resp == 1  # index 1 == EOF
+
 if __name__ == "__main__":
     unittest.main()