Use unicode escape sequence for file type
Use larger range of random digits to avoid collisions in test

Previous we had 5000 combinations, now we have 36 ^ 10.
Remove test with spaces

These will be part of another pull request.
Merge branch 'fix-windows-integ-test' into develop

* fix-windows-integ-test:
  Remove test with spaces
  Use larger range of random digits to avoid collisions in test
  Use unicode escape sequence for file type