Reorganize test directory

[yuxiang-he]

Checklist

General Contributing

• Have you read the Code of Conduct and signed the CLA?

Is This a Code Change?

• Non-code related change (markdown/git settings etc)
• SDK Code Change
• Example/Test Code Change

Validation

• Does tox pass?
• Do the tests pass?

[codecov]

Codecov Report

Merging #312 (20ab15d) into main (5af34a4) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main     #312   +/-   ##
=======================================
  Coverage   63.55%   63.55%           
=======================================
  Files          30       30           
  Lines       48701    48701           
  Branches     3580     3580           
=======================================
  Hits        30954    30954           
  Misses      17719    17719           
  Partials       28       28           

Flag	Coverage Δ
unit	63.55% <ø> (ø)

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