Why I did it
The 720DT-48S platform has variants with different chassis names, and these need to all be included in platform_components.json to ensure that sonic-mgmt platform_tests/fwutil/test_fwutil.py::test_fwutil_show passes
How I did it
Updated platform_components.json with the variant names for 720DT-48S.
How to verify it
Ran aforementioned testcase and verified that it passes on the different variants.
Why I did it
Add components data for sonic-mgmt testing
How I did it
Update platform.json and add platform_components.json
How to verify it
Ran sonic-mgmt tests (test_chassis and test_component)
