PEP8 compliant tests

Some small formatting changes that fix the following PEP8 compliance warnings :) :

    sample_test.py:4:1: E302 expected 2 blank lines, found 1
    sample_test.py:7:27: E231 missing whitespace after ':'
    sample_test.py:7:49: E231 missing whitespace after ':'
    sample_test.py:8:55: E228 missing whitespace around modulo operator
    sample_test.py:8:80: E501 line too long (97 > 79 characters)
    sample_test.py:12:65: E261 at least two spaces before inline comment
    sample_test.py:12:80: E501 line too long (95 > 79 characters)
    sample_test.py:37:9: E301 expected 1 blank line, found 0