command output not registered

[Larry Fast]

In the following example echo_out.stdout is properly populated with "hello"  but cat_testfile.stdout and tail_testfile are both empty.  My real use case is to do a pass/fail test on an external command that dumps it's output to a file.  

    - command: echo hello

      register: echo_out

 

    - command: cat /tmp/testfile

      register: cat_testfile

    - command: tail /tmp/testfile

      register: cat_testfile

[Larry Fast]

Resolved.  my testfile (output from my external command) contained control characters that caused Ansible's logging to silently fail.  I'm guessing it was corrupting the JSON output.  The control character was ^[  part of color coding the output.