failing test on rpi

[thijstriemstra]

platform linux2 -- Python 2.7.9, pytest-3.0.6, py-1.4.32, pluggy-0.4.0 -- /home/pi/projects/pi-test/luma.lcd/.tox/py27/bin/python2.7
cachedir: .cache
rootdir: /home/pi/projects/pi-test/luma.lcd, inifile: 
plugins: cov-2.4.0
collected 12 items 

tests/test_backlight.py::test_unsupported_platform FAILED
tests/test_backlight.py::test_init PASSED
tests/test_backlight.py::test_enable_on PASSED
tests/test_backlight.py::test_enable_off PASSED
tests/test_pcd8544.py::test_init_84x48 PASSED
tests/test_pcd8544.py::test_hide PASSED
tests/test_pcd8544.py::test_show PASSED
tests/test_pcd8544.py::test_display PASSED
tests/test_st7735.py::test_init_160x128 PASSED
tests/test_st7735.py::test_hide PASSED
tests/test_st7735.py::test_show PASSED
tests/test_st7735.py::test_display PASSED

================================================================ FAILURES ================================================================
_______________________________________________________ test_unsupported_platform ________________________________________________________

    def test_unsupported_platform():
        with pytest.raises(luma.core.error.UnsupportedPlatform) as ex:
>           backlight(bcm_LIGHT=19)
E           Failed: DID NOT RAISE <class 'luma.core.error.UnsupportedPlatform'>

tests/test_backlight.py:30: Failed
================================================== 1 failed, 11 passed in 5.92 seconds ===================================================
ERROR: InvocationError: '/home/pi/projects/pi-test/luma.lcd/.tox/py27/bin/coverage run -m py.test -v'