feat: add single get api

[ppetpadriew]

feat:

• single get api

fix:

• we use fresh() so that the system return every fields in the model not just the fields that are in payload pass in the model during initialization.

test:

• add missing tests
• refactor test pattern

[ppetpadriew]

awaiting for move common logic to base test class

[ppetpadriew]

remaining move GET logic to base class