Files

Paul de Raaij d345e522bd feat: add generic Value[T] base class for value objects

- Create Value[T] (frozen dataclass + ABC + Generic) in domain/framework/
- Migrate ClassifiedAdTitle and ClassifiedAdText to inherit Value[str]
- Standardize all value access via .value instead of type-specific fields

2026-07-29 11:13:17 -04:00

1.7 KiB

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Plan: Value Object Base Class

Goal

Create a generic Value[T] base class in the framework layer. All value objects standardize on .value access via inheritance.

Design

`Value[T]` base class (`domain/framework/value.py`)

@dataclass(frozen=True)
class Value(ABC, Generic[T]):
    value: T

Frozen dataclass → immutability + structural equality (core Value Object semantics)
Generic[T] → type-safe .value access in subclasses (e.g., Value[str])
ABC → mirrors the Entity pattern

Subclasses

ClassifiedAdTitle(Value[str]) — drops title: str, inherits value: T bound to str
ClassifiedAdText(Value[str]) — drops text: str, inherits value: T bound to str

Ripple effects

Every .title / .text reference on these objects becomes .value:

classified_ad.py — self.title.title → self.title.value, construction calls, method bodies
Tests — assertions, constructions, equality checks

Files changed

File	Change
`domain/framework/value.py`	New — `Value[T]` base class
`domain/framework/__init__.py`	Add `Value` re-export
`domain/marketplace/classified_ad_title.py`	Inherit `Value[str]`, rename field
`domain/marketplace/classified_ad_text.py`	Inherit `Value[str]`, rename field
`domain/marketplace/classified_ad.py`	Update `.title`/`.text` refs → `.value`
`tests/test_classified_ad_title.py`	Update refs
`tests/test_classified_ad_text.py`	Update refs
`tests/test_classified_ad.py`	Update refs

Not in scope

ClassifiedAdId, UserId, Money, Price — stay as-is.

Verification

pytest tests/ — all 63 tests pass
ruff check . && ruff format --check . — clean

1.7 KiB Raw Blame History