Thank you for explanation! Next time I will be more attentive.

Python, Basic Tests:
"False should equal True" for Test.assert_equals(substring_test("supercalifragilisticexpialidocious","SoundOfItIsAtrocious"), True)
str2 has "n" and str1 has not. So should be False.
Please fix.

['-3->0'] should equal ['-2', '0', '-1', '-3->-2']. Please fix.

--- Just couple lines from output (tests between populations deleted)

Random tests
Dictionary populated with ['gypf', 'dhk', 'tgojx', 'ygchn']
Dictionary populated with ['z', 'je', 'igm', 'uepwg']
Dictionary populated with ['vp', 'ycap', 'gwqau', 'xm', 'aahua']
Testing for y....
It should work for random inputs too: True should equal False

--- Why should equal "False"? 'y....' matches 'ygchn', so "True" should be. Or random tests work just with last population? Please explain.