Fix TestIndexFixtures

[KyleMaas]

Ran successfully 22 times without errors. This one takes a while to run.

Fixes #279

See also #237

[decentral1se]

That's strange, it's failing with the same error reported in #279 🤔

[KyleMaas]

I think I found the problem. Upon closer inspection, I noticed I had a file not added to git. Turns out the test's download script would fail with an error code of 0 (success) the first time you ran it, but would run just fine on subsequent runs, which is why it worked for me. But since the CI system is always starting from a blank slate, it was neither working correctly (failing) nor failing out the script where it would log the output (returning 0). This latest commit should fix that.

[decentral1se]

Amazing, thanks!

[KyleMaas]

Thanks!