Merge branch 'master' into doc_additions

Author: kotfu

CHANGELOG.md

@@ -1,6 +1,7 @@
 ## 0.9.17 (TBD, 2019)
 * Bug Fixes
     * Fixed a bug when using WSL when all Windows paths have been removed from $PATH
+    * Fixed a bug when running a cmd2 application on Linux without Gtk libraries installed
 * Enhancements
     * No longer treating empty text scripts as an error condition
 

cmd2/clipboard.py

@@ -10,8 +10,9 @@
 try:
     # Try getting the contents of the clipboard
     _ = pyperclip.paste()
-except (PyperclipException, FileNotFoundError):
+except (PyperclipException, FileNotFoundError, ValueError):
     # NOTE: FileNotFoundError is for Windows Subsystem for Linux (WSL) when Windows paths are removed from $PATH
+    # NOTE: ValueError is for headless Linux systems without Gtk installed
     can_clip = False
 else:
     can_clip = True

cmd2/cmd2.py

@@ -2046,7 +2046,7 @@ def _redirect_output(self, statement: Statement) -> Tuple[bool, utils.Redirectio
         elif statement.output:
             import tempfile
             if (not statement.output_to) and (not self._can_clip):
-                self.perror("Cannot redirect to paste buffer; install 'pyperclip' and re-run to enable")
+                self.perror("Cannot redirect to paste buffer; missing 'pyperclip' and/or pyperclip dependencies")
                 redir_error = True
 
             elif statement.output_to:

tests/test_cmd2.py

@@ -1332,7 +1332,7 @@ def test_clipboard_failure(base_app, capsys):
     # Make sure we got the error output
     out, err = capsys.readouterr()
     assert out == ''
-    assert "Cannot redirect to paste buffer; install 'pyperclip' and re-run to enable" in err
+    assert 'Cannot redirect to paste buffer;' in err and 'pyperclip' in err
 
 
 class CommandResultApp(cmd2.Cmd):