current folder structure:
.
└── sample (project-root)
├── sample (plugin-root)
│ ├── includes
│ │ └── functions.php
│ ├── languages
│ │ ├── sample-ja.mo
│ │ ├── sample-ja.po
│ │ └── sample.pot
│ ├── public
│ └── sample.php
└── tests (put unit test files here)
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What the core repository does is place tests with each different version. It makes sense for you to do the same.
Disclaimer: I have nothing to do with the plugins review team. I could be completely wrong from their perspective.
]]>And I got the following link as a reference.
https://make.www.ads-software.com/cli/handbook/plugin-unit-tests/