It seems to me that your example does work. I use the tab delimited approach, but that shouldn't be the cause.
*** Setting ***
Variables globe.py
*** Variables ***
${myTest} ${a}
*** Test Cases ***
A Test Case
Log To Console ${myTest}
This resulted into this response from Robot Framework which appears to be what you're looking for.
Suite Executor: Robot Framework 3.0 (Python 2.7.9 on win32)
==============================================================================
MyLibrary
==============================================================================
MyLibrary.Test
==============================================================================
A Test Case this is testing
| PASS |
------------------------------------------------------------------------------
MyLibrary.Test | PASS |
1 critical test, 1 passed, 0 failed
1 test total, 1 passed, 0 failed
==============================================================================
MyLibrary | PASS |
1 critical test, 1 passed, 0 failed
1 test total, 1 passed, 0 failed
==============================================================================