Check for illegal inputs

[AppVeyorBot]

:x: Build rotest 1.0.1368 failed (commit https://github.com/gregoil/rotest/commit/09f48688e5 by @UnDarkle)

[coveralls]

Pull Request Test Coverage Report for Build 1525

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 92 unchanged lines in 16 files lost coverage.
• Overall coverage decreased (-0.07%) to 85.274%

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Files with Coverage Reduction	New Missed Lines	%
.tox/py27-django1.8/lib/python2.7/site-packages/rotest/core/flow_component.py	2	91.18%
.tox/py27-django1.8/lib/python2.7/site-packages/rotest/core/result/handlers/stream/stream_handler.py	2	69.44%
.tox/py27-django1.9/lib/python2.7/site-packages/rotest/core/flow_component.py	2	91.18%
.tox/py27-django1.9/lib/python2.7/site-packages/rotest/core/result/handlers/stream/stream_handler.py	2	69.44%
.tox/py36-django1.8/lib/python3.6/site-packages/rotest/core/flow_component.py	2	91.18%
.tox/py36-django1.8/lib/python3.6/site-packages/rotest/core/result/handlers/stream/stream_handler.py	2	69.44%
.tox/py37-django1.8/lib/python3.7/site-packages/rotest/core/flow_component.py	2	91.18%
.tox/py37-django1.8/lib/python3.7/site-packages/rotest/core/result/handlers/stream/stream_handler.py	2	69.44%
.tox/py27-django1.8/lib/python2.7/site-packages/rotest/core/result/handlers/stream/base_handler.py	3	82.93%
.tox/py27-django1.9/lib/python2.7/site-packages/rotest/core/result/handlers/stream/base_handler.py	3	82.93%
<!--	Total:	92		-->

Totals
Change from base Build 1499:	-0.07%
Covered Lines:	12907
Relevant Lines:	15136

---

💛 - Coveralls

[AppVeyorBot]

:x: Build rotest 1.0.1370 failed (commit https://github.com/gregoil/rotest/commit/4b1d12fa29 by @UnDarkle)

[AppVeyorBot]

:x: Build rotest 1.0.1372 failed (commit https://github.com/gregoil/rotest/commit/43b2a8ce0c by @gregoil)