refactor: move post_processing to unittest

[zhaoyongjie]

SUMMARY

This PR decouple post-processing unit test and move it from the integration_test to the unit_tests. In order to make life easy, replace class test cases with functional test cases.

ADDITIONAL INFORMATION

• Has associated issue:
• Required feature flags:
• Changes UI
• Includes DB Migration (follow approval process in SIP-59)
  • Migration is atomic, supports rollback & is backwards-compatible
  • Confirm DB migration upgrade and downgrade tested
  • Runtime estimates and downtime expectations provided
• Introduces new feature or API
• Removes existing feature or API

[codecov]

Codecov Report

Merging #18779 (a2c38a6) into master (2421d17) will increase coverage by 0.00%.
The diff coverage is 100.00%.

❗ Current head a2c38a6 differs from pull request most recent head ead18f1. Consider uploading reports for the commit ead18f1 to get more accurate results

@@           Coverage Diff           @@
##           master   #18779   +/-   ##
=======================================
  Coverage   66.32%   66.32%           
=======================================
  Files        1620     1620           
  Lines       63087    63092    +5     
  Branches     6372     6372           
=======================================
+ Hits        41840    41845    +5     
  Misses      19590    19590           
  Partials     1657     1657           

Flag	Coverage Δ
hive	52.22% <60.00%> (+<0.01%)	⬆️
mysql	81.43% <100.00%> (+<0.01%)	⬆️
postgres	81.47% <100.00%> (+<0.01%)	⬆️
presto	52.07% <60.00%> (+<0.01%)	⬆️
python	81.91% <100.00%> (+<0.01%)	⬆️
sqlite	81.16% <100.00%> (+<0.01%)	⬆️

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Impacted Files	Coverage Δ
superset/common/query_object.py	95.67% <100.00%> (+0.04%)	⬆️
...perset/utils/pandas_postprocessing/contribution.py	100.00% <100.00%> (ø)

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[villebro]

Love the change to proper unit tests! One question about the change in the contribution operator - should we potentially split this PR in two - the first for the refactor, and the second for the functional change once the refactor has been merged?

[villebro]

Are we sure we want to display infinities as 0? I think having 1/0 to result in null to be more intuitive. I assume keeping infinities as null would cause a break in the chart as opposed to it dropping to zero, which IMO feels more intuitive.

[zhaoyongjie]

let us discuss this in new PR.

[zhaoyongjie]

Love the change to proper unit tests! One question about the change in the contribution operator - should we potentially split this PR in two - the first for the refactor, and the second for the functional change once the refactor has been merged?

it's my bad. I'm gonna split it to 2 PRs.

[villebro]

LGTM! 🚀