test(wyh):add plot test code

[Weiyuhong-1998]

Description

Add plot test codes, including compare two pictures, do things in an isolated directory

Related Issue

#323

TODO

Check List

• merge the latest version source branch/repo, and resolve all the conflicts
• pass style check
• pass all the tests

[codecov]

Codecov Report

Merging #370 (fa74db3) into main (c901a00) will decrease coverage by 0.02%.
The diff coverage is 100.00%.

❗ Current head fa74db3 differs from pull request most recent head 43a84ba. Consider uploading reports for the commit 43a84ba to get more accurate results

@@            Coverage Diff             @@
##             main     #370      +/-   ##
==========================================
- Coverage   85.99%   85.97%   -0.03%     
==========================================
  Files         522      522              
  Lines       41112    41140      +28     
==========================================
+ Hits        35355    35369      +14     
- Misses       5757     5771      +14     

Flag	Coverage Δ
unittests	85.97% <100.00%> (-0.03%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
ding/utils/tests/test_plot.py	100.00% <100.00%> (ø)
ding/model/template/atoc.py	86.31% <0.00%> (-8.95%)	⬇️
ding/worker/learner/comm/flask_fs_learner.py	83.12% <0.00%> (-6.88%)	⬇️
ding/envs/env_manager/envpool_env_manager.py	37.34% <0.00%> (-3.75%)	⬇️
ding/utils/data/dataloader.py	44.55% <0.00%> (-1.56%)	⬇️
ding/worker/learner/tests/test_base_learner.py	91.01% <0.00%> (-1.13%)	⬇️
ding/envs/env_manager/subprocess_env_manager.py	76.72% <0.00%> (-0.99%)	⬇️
ding/entry/__init__.py	100.00% <0.00%> (ø)
ding/world_model/ddppo.py	76.08% <0.00%> (+0.31%)	⬆️
...envs/env_manager/tests/test_envpool_env_manager.py	38.46% <0.00%> (+2.74%)	⬆️
... and 2 more

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