We should add the following tests for ServiceEntryPointShardRole:

• Tests for parsing behavior
• Message failing parse logs "Assertion while parsing command" and generates the right error response

• Tests for command selection
• Message with invalid command name logs "Assertion while executing command" and  generates the right error response

• Tests for response generation 
• Tests for appending information to the response
• Append error labels and topology version information
• Append cluster and operation time

• Tests for opCtx storing maxTimeMS behavior
• maxTimeMS behavior for getMores

• Tests for exception behavior in various areas of ServiceEntryPoint
• Tests for RunCommandOpTimes tracking
• Test for command retry working as expected
• Tests for failure cases preventing command retry

• Tests for ReadConcern extraction
• Tests for database refresh and errors during database refresh