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.

2 files changed, 64 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
diff --git a/tests/test_transcript.py b/tests/test_transcript.py
index 302d80c8..3caf6a37 100644
--- a/tests/test_transcript.py
+++ b/tests/test_transcript.py
@@ -154,6 +154,32 @@ this is a \/multiline\/ command
 
     assert transcript == expected
 
+def test_history_transcript_bad_filename(request, capsys):
+    app = CmdLineApp()
+    app.stdout = StdOut()
+    run_cmd(app, 'orate this is\na /multiline/\ncommand;\n')
+    run_cmd(app, 'speak /tmp/file.txt is not a regex')
+
+    expected = r"""(Cmd) orate this is
+> a /multiline/
+> command;
+this is a \/multiline\/ command
+(Cmd) speak /tmp/file.txt is not a regex
+\/tmp\/file.txt is not a regex
+"""
+
+    # make a tmp file
+    history_fname = '~/fakedir/this_does_not_exist.txt'
+
+    # tell the history command to create a transcript
+    run_cmd(app, 'history -t "{}"'.format(history_fname))
+
+    # read in the transcript created by the history command
+    with pytest.raises(FileNotFoundError):
+        with open(history_fname) as f:
+            transcript = f.read()
+        assert transcript == expected
+
 @pytest.mark.parametrize('expected, transformed', [
     # strings with zero or one slash or with escaped slashes means no regular
     # expression present, so the result should just be what re.escape returns.