Fixed a couple potential crashes on opening files

Fixed crashes that occur when attempting to open a file in a non-existent directory or a when the filename is too long.

Specifically fixed this when redirecting output to a file and when saving a transcript based on the history.

Also added a couple unit tests related to the fixes.

1 files changed, 38 insertions, 0 deletions

diff --git a/tests/test_cmd2.py b/tests/test_cmd2.py
index 24a14ea2..37592da1 100644
--- a/tests/test_cmd2.py
+++ b/tests/test_cmd2.py
@@ -615,6 +615,44 @@ def test_output_redirection(base_app):
     finally:
         os.remove(filename)
 
+def test_output_redirection_to_nonexistent_directory(base_app):
+    filename = '~/fakedir/this_does_not_exist.txt'
+
+    # Verify that writing to a file in a non-existent directory doesn't work
+    run_cmd(base_app, 'help > {}'.format(filename))
+    expected = normalize(BASE_HELP)
+    with pytest.raises(FileNotFoundError):
+        with open(filename) as f:
+            content = normalize(f.read())
+        assert content == expected
+
+    # Verify that appending to a file also works
+    run_cmd(base_app, 'help history >> {}'.format(filename))
+    expected = normalize(BASE_HELP + '\n' + HELP_HISTORY)
+    with pytest.raises(FileNotFoundError):
+        with open(filename) as f:
+            content = normalize(f.read())
+        assert content == expected
+
+def test_output_redirection_to_too_long_filename(base_app):
+    filename = '~/sdkfhksdjfhkjdshfkjsdhfkjsdhfkjdshfkjdshfkjshdfkhdsfkjhewfuihewiufhweiufhiweufhiuewhiuewhfiuwehfiuewhfiuewhfiuewhfiuewhiuewhfiuewhfiuewfhiuwehewiufhewiuhfiweuhfiuwehfiuewfhiuwehiuewfhiuewhiewuhfiuewhfiuwefhewiuhewiufhewiufhewiufhewiufhewiufhewiufhewiufhewiuhewiufhewiufhewiuheiufhiuewheiwufhewiufheiufheiufhieuwhfewiuhfeiufhiuewfhiuewheiwuhfiuewhfiuewhfeiuwfhewiufhiuewhiuewhfeiuwhfiuwehfuiwehfiuehiuewhfieuwfhieufhiuewhfeiuwfhiuefhueiwhfw'
+
+    # Verify that writing to a file in a non-existent directory doesn't work
+    run_cmd(base_app, 'help > {}'.format(filename))
+    expected = normalize(BASE_HELP)
+    with pytest.raises(OSError):
+        with open(filename) as f:
+            content = normalize(f.read())
+        assert content == expected
+
+    # Verify that appending to a file also works
+    run_cmd(base_app, 'help history >> {}'.format(filename))
+    expected = normalize(BASE_HELP + '\n' + HELP_HISTORY)
+    with pytest.raises(OSError):
+        with open(filename) as f:
+            content = normalize(f.read())
+        assert content == expected
+
 
 def test_feedback_to_output_true(base_app):
     base_app.feedback_to_output = True