[TST] Additional smoke tests for stats.py

[monicayao]

Addresses #376 .
Replica of PR#378, where codedev decreased coverage somehow

Changes proposed in this pull request:

• Compared to last time, I have synced my master up to date with the current tedana
• I added the code directly on Github instead of on my IDE (which may have caused some issue)

[jbteves]

LGTM, thanks @monicayao !

[jbteves]

Wait, now we have no codecov at all...

[emdupre]

The failure to show coverage is a more general problem with our CircleCI config. We're getting this error at coverage upload:

#!/bin/bash -eo pipefail
curl -s https://codecov.io/bash | bash -s -- \
  -f "/tmp/src/coverage/coverage.xml" \
  -t "${CODECOV_TOKEN}" \
  -n "${CIRCLE_BUILD_NUM}" \
  -y ".codecov.yml" \
  -F "" \
  -Z || echo 'Codecov upload failed'

/bin/bash: curl: command not found
Codecov upload failed

I'm going to go ahead and merge this, since a previous PR showed increased coverage.

Thanks, @monicayao and @jbteves !

[jbteves]

@all-contributors please add @monicayao for testing

[allcontributors]

@jbteves

I've put up a pull request to add @monicayao! 🎉