TST: add back test_generic.py, accid removed in the big reorg

[jreback]

No description provided.

[jreback]

somehow this file got removed a while back. I split it up a bit in any event.

[codecov]

Codecov Report

Merging #18114 into master will increase coverage by 0.15%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master   #18114      +/-   ##
==========================================
+ Coverage   91.25%   91.41%   +0.15%     
==========================================
  Files         163      163              
  Lines       50124    50126       +2     
==========================================
+ Hits        45742    45822      +80     
+ Misses       4382     4304      -78

Flag	Coverage Δ
#multiple	89.22% <100%> (+0.17%)	⬆️
#single	40.32% <0%> (-0.07%)	⬇️

Impacted Files	Coverage Δ
pandas/core/generic.py	95.72% <100%> (+3.3%)	⬆️
pandas/io/gbq.py	25% <0%> (-58.34%)	⬇️
pandas/core/frame.py	97.8% <0%> (-0.05%)	⬇️
pandas/core/internals.py	94.54% <0%> (+0.07%)	⬆️
pandas/core/panel.py	97.28% <0%> (+0.28%)	⬆️
pandas/plotting/_converter.py	65.2% <0%> (+1.81%)	⬆️
pandas/core/common.py	93% <0%> (+1.82%)	⬆️

---

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[codecov]

Codecov Report

Merging #18114 into master will increase coverage by 0.1%.
The diff coverage is 83.33%.

@@            Coverage Diff            @@
##           master   #18114     +/-   ##
=========================================
+ Coverage   91.28%   91.39%   +0.1%     
=========================================
  Files         163      163             
  Lines       50130    50132      +2     
=========================================
+ Hits        45761    45817     +56     
+ Misses       4369     4315     -54

Flag	Coverage Δ
#multiple	89.2% <83.33%> (+0.12%)	⬆️
#single	40.33% <8.33%> (-0.06%)	⬇️

Impacted Files	Coverage Δ
pandas/util/testing.py	100% <ø> (ø)	⬆️
pandas/core/generic.py	95.72% <83.33%> (+3.3%)	⬆️
pandas/io/gbq.py	25% <0%> (-58.34%)	⬇️
pandas/plotting/_converter.py	63.38% <0%> (-1.82%)	⬇️
pandas/core/frame.py	97.8% <0%> (-0.05%)	⬇️
pandas/core/internals.py	94.54% <0%> (+0.07%)	⬆️
pandas/core/panel.py	97.28% <0%> (+0.28%)	⬆️
pandas/core/common.py	93% <0%> (+1.82%)	⬆️

---

Continue to review full report at Codecov.

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Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 8441f02...a63f66d. Read the comment docs.