First past at unit test for persistent history feature

Added pexpect to modules required for running unit tests.

This opens the door for carefully crafted complex unit tests to verify intricate behavior.  Tests like this are somewhat painful to write and slow to execute.  However, they can enable testing complicated interactive behavior that we otherwise probably would not be able to test.

1 files changed, 27 insertions, 0 deletions

diff --git a/tests/test_cmd2.py b/tests/test_cmd2.py
index 5f56803d..454fdc1f 100644
--- a/tests/test_cmd2.py
+++ b/tests/test_cmd2.py
@@ -11,6 +11,7 @@ import io
 import tempfile
 
 import mock
+import pexpect
 import pytest
 import six
 
@@ -1525,3 +1526,29 @@ def test_poutput_none(base_app):
     out = base_app.stdout.buffer
     expected = ''
     assert out == expected
+
+
+def test_persistent_history(request):
+    test_dir = os.path.dirname(request.module.__file__)
+    persistent_app = os.path.join(test_dir, '..', 'examples', 'persistent_history.py')
+
+    # STart an instance of the persistent history example and send it a few commands
+    child = pexpect.spawn(persistent_app)
+    prompt = 'ph> '
+    child.expect(prompt)
+    child.sendline('help')
+    child.expect(prompt)
+    child.sendline('help history')
+    child.expect(prompt)
+    child.sendline('quit')
+    child.close()
+
+    # Start a 2nd instance of the persistent history example and send it an up arrow to verify persistent history
+    up_arrow = '\x1b[A'
+    child2 = pexpect.spawn(persistent_app)
+    child2.expect(prompt)
+    child2.send(up_arrow)
+    child2.expect('quit', timeout=5)
+    assert child2.after == b'quit'
+
+