Add extensive unit tests

[dguerri]

Summary

• add test coverage for rpc helper functions
• cover SetAttrRequest methods
• test osFS helper
• verify RPC client factory works via net/rpc
• add DockerFuseClient operation tests
• exercise additional Node operations

Testing

• go test ./...

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https://chatgpt.com/codex/tasks/task_e_687b7f706ee083238bfd4507ead21df5

[coveralls]

Pull Request Test Coverage Report for Build 16388890893

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 19 unchanged lines in 1 file lost coverage.
• Overall coverage increased (+21.4%) to 54.516%

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Files with Coverage Reduction	New Missed Lines	%
pkg/rpccommon/utils.go	19	14.73%

Totals
Change from base Build 16387127332:	21.4%
Covered Lines:	839
Relevant Lines:	1539

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💛 - Coveralls