YAML results don't display correctly as literal strings

[Javier Collado]

Sometimes the yaml output doesn't display as literal strings the output from commands like in the following fragment:

  stderr: "DEBUG: Calling 'ls /tmp/tmpLsm5FK'\nDEBUG: stdout: file1\nfile2\nfile3\n\
    \nDEBUG: stderr: \nDEBUG: returncode: 0\nDEBUG: Checking for 'file1' in 'ls' output\n\
    DEBUG: Checking for 'file2' in 'ls' output\nDEBUG: Checking for 'file3' in 'ls'\
    \ output\nDEBUG: Calling 'ls -l /tmp/tmpLsm5FK/file1'\nDEBUG: stdout: -r-xr-xr-x\
    \ 1 root root 0 Oct 25 13:01 /tmp/tmpLsm5FK/file1\n\nDEBUG: stderr: \nDEBUG: returncode:\
    \ 0\nDEBUG: Calling 'ls -l /tmp/tmpLsm5FK/file2'\nDEBUG: stdout: -rw-rw-rw- 1\
    \ root root 0 Oct 25 13:01 /tmp/tmpLsm5FK/file2\n\nDEBUG: stderr: \nDEBUG: returncode:\
    \ 0\nDEBUG: Calling 'ls -l /tmp/tmpLsm5FK/file3'\nDEBUG: stdout: -rwxrwxrwx 1\
    \ root root 0 Oct 25 13:01 /tmp/tmpLsm5FK/file3\n\nDEBUG: stderr: \nDEBUG: returncode:\
    \ 0\n"

Note: this bug is related to: bug1040753

[Javier Collado (javier.collado)]

The problem is that yaml doesn't serialize as literal string those that have whitespace characters before a newline character as in the following example:

>>> import yaml
>>> print yaml.dump('hello world\n', default_style='|')
|
  hello world

>>> print yaml.dump('hello world \n', default_style='|')
"hello world \n"

The solution would be to make sure that whitespace is removed, so that the strings are serialized as expected.