offload atlas downloading to separate thread

[alessandrofelder]

Description

What is this PR

• [ ] Bug fix
• [x] Addition of a new feature
• [ ] Other

Why is this PR needed? Downloading an atlas should not block the napari viewer

What does this PR do? Offloads the atlas downloading to a separate thread.

References

Closes #7

How has this PR been tested?

Existing unit test adapted to wait for worker to finish.

Is this a breaking change?

Nope.

Does this PR require an update to the documentation?

n/a

Checklist:

• [x] The code has been tested locally
• [x] Tests have been added to cover all new functionality (unit & integration)
• [x] The documentation has been updated to reflect any changes
• [x] The code has been formatted with pre-commit

[alessandrofelder]

Needs to be rebased onto #67

[willGraham01]

Not sure what the rebase has done, but this looks like it's a bug in the unit test itself rather than in the implementation.

I can pip install -e . this branch, and quite happily be downloading a new atlas whilst looking at an existing one (see below). This is in a clean mamba environment with python 3.8 (which is the failing case).

Updates:

• Tests pass on Ubuntu 22.04 w/ python 3.10

[alessandrofelder]

Argh! I know what's likely happening: my assumption didn't hold on the CI... (and this then breaks the rest of the tests :cry: )

I'll have to do a small refactor

[willGraham01]

Argh! I know what's likely happening: my assumption didn't hold on the CI... (and this then breaks the rest of the tests 😢 )

I'm able to get the tests to pass w/ Python 3.8, 3.9, and 3.10 via tox locally, so that provides extra evidence for your claim.

[codecov[bot]]

Codecov Report

Patch coverage: 85.71% and project coverage change: -0.61% :warning:

Comparison is base (adf5ce6) 97.32% compared to head (3590a0e) 96.72%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #63 +/- ## ========================================== - Coverage 97.32% 96.72% -0.61% ========================================== Files 7 7 Lines 299 305 +6 ========================================== + Hits 291 295 +4 - Misses 8 10 +2 ``` | [Files Changed](https://app.codecov.io/gh/brainglobe/brainrender-napari/pull/63?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=brainglobe) | Coverage Δ | | |---|---|---| | [brainrender\_napari/widgets/atlas\_table\_view.py](https://app.codecov.io/gh/brainglobe/brainrender-napari/pull/63?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=brainglobe#diff-YnJhaW5yZW5kZXJfbmFwYXJpL3dpZGdldHMvYXRsYXNfdGFibGVfdmlldy5weQ==) | `97.89% <85.71%> (-2.11%)` | :arrow_down: |

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[alessandrofelder]

The line that codeCov is unhappy about is actually covered implicitly, because the test checks the the argument of the emitted signal, which is the return value of the thread worker