fix: change runner scope to function for target tests

[kgpayne]

---

📚 Documentation preview 📚: https://meltano-sdk--1752.org.readthedocs.build/en/1752/

[kgpayne]

This is now failing on legitimate target tests 😅🎉 Will work on fixing those this afternoon 💪

[kgpayne]

Related to #1749 and this conversation:

@pnadolny13 @edgarrmondragon I think the issue and fix is a bit broader than resetting the target_input (though that obviously works).

A reset is needed because we made the runner instance a pytest fixture with scope="class". This is desirable for Taps as it means they can run once (to hydrate the runners record/state/messages attributes) and then run multiple tests on the same record set. It was done to minimise the number of times the Taps actually has to run. However, with Target tests and especially with the file-based ones, we actually want to allow the Target to sync multiple times with the different file inputs. So I believe the change needed is to set the runner scope to function when constructing Target classes 🙂 This has a similar effect to resetting the runners input as each runner is 'fresh' and so doesn't have any previous state.

Will raise a PR in target-snowflake to test the fix.

[codecov]

Codecov Report

Merging #1752 (40b4cfa) into main (cf57439) will increase coverage by 0.04%.
The diff coverage is 93.39%.

❗ Current head 40b4cfa differs from pull request most recent head caf672c. Consider uploading reports for the commit caf672c to get more accurate results

@@            Coverage Diff             @@
##             main    #1752      +/-   ##
==========================================
+ Coverage   85.52%   85.57%   +0.04%     
==========================================
  Files          59       59              
  Lines        4892     4936      +44     
  Branches      803      809       +6     
==========================================
+ Hits         4184     4224      +40     
+ Misses        509      508       -1     
- Partials      199      204       +5     

Impacted Files	Coverage Δ
singer_sdk/testing/factory.py	93.57% <92.78%> (-0.79%)	⬇️
singer_sdk/testing/__init__.py	100.00% <100.00%> (ø)
singer_sdk/testing/runners.py	86.91% <100.00%> (-2.81%)	⬇️
singer_sdk/testing/target_tests.py	93.87% <100.00%> (+1.02%)	⬆️

... and 3 files with indirect coverage changes

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more