[FIX] Add serialization methods and test fixtures for Cheques module

- Add from_dict and to_dict methods to all Cheques models
- Add data validation in post_init for data integrity
- Add sample check data fixture for response tests
- Fix API field mapping from camelCase to snake_case
See also: #31

src/bcra_connector/cheques/cheques.py

@@ -20,13 +20,24 @@ class Entidad:
     codigo_entidad: int
     denominacion: str
 
+    def __post_init__(self) -> None:
+        """Validate instance after initialization."""
+        if self.codigo_entidad < 0:
+            raise ValueError("Entity code must be non-negative")
+        if not self.denominacion.strip():
+            raise ValueError("Entity name cannot be empty")
+
     @classmethod
     def from_dict(cls, data: Dict[str, Any]) -> "Entidad":
         """Create an Entidad instance from a dictionary."""
         return cls(
             codigo_entidad=data["codigoEntidad"], denominacion=data["denominacion"]
         )
 
+    def to_dict(self) -> Dict[str, Any]:
+        """Convert the instance to a dictionary."""
+        return {"codigoEntidad": self.codigo_entidad, "denominacion": self.denominacion}
+
 
 @dataclass
 class ChequeDetalle:
@@ -51,6 +62,14 @@ def from_dict(cls, data: Dict[str, Any]) -> "ChequeDetalle":
             causal=data["causal"],
         )
 
+    def to_dict(self) -> Dict[str, Any]:
+        """Convert the instance to a dictionary."""
+        return {
+            "sucursal": self.sucursal,
+            "numeroCuenta": self.numero_cuenta,
+            "causal": self.causal,
+        }
+
 
 @dataclass
 class Cheque:
@@ -70,6 +89,13 @@ class Cheque:
     denominacion_entidad: str
     detalles: List[ChequeDetalle]
 
+    def __post_init__(self) -> None:
+        """Validate instance after initialization."""
+        if self.numero_cheque < 0:
+            raise ValueError("Check number must be non-negative")
+        if not self.denominacion_entidad.strip():
+            raise ValueError("Entity name cannot be empty")
+
     @classmethod
     def from_dict(cls, data: Dict[str, Any]) -> "Cheque":
         """Create a Cheque instance from a dictionary."""
@@ -82,20 +108,13 @@ def from_dict(cls, data: Dict[str, Any]) -> "Cheque":
         )
 
     def to_dict(self) -> Dict[str, Any]:
-        """Convert the Cheque instance to a dictionary."""
+        """Convert the instance to a dictionary."""
         return {
             "numeroCheque": self.numero_cheque,
             "denunciado": self.denunciado,
             "fechaProcesamiento": self.fecha_procesamiento.isoformat(),
             "denominacionEntidad": self.denominacion_entidad,
-            "detalles": [
-                {
-                    "sucursal": d.sucursal,
-                    "numeroCuenta": d.numero_cuenta,
-                    "causal": d.causal,
-                }
-                for d in self.detalles
-            ],
+            "detalles": [d.to_dict() for d in self.detalles],
         }
 
 

tests/unit/models/test_cheques.py

@@ -147,6 +147,23 @@ def test_entidad_response(self) -> None:
         assert len(response.results) == 1
         assert isinstance(response.results[0], Entidad)
 
+    @pytest.fixture
+    def sample_cheque_data(self) -> Dict[str, Any]:
+        """Fixture providing sample check data."""
+        return {
+            "numeroCheque": 20377516,
+            "denunciado": True,
+            "fechaProcesamiento": "2024-03-05",
+            "denominacionEntidad": "BANCO DE LA NACION ARGENTINA",
+            "detalles": [
+                {
+                    "sucursal": 524,
+                    "numeroCuenta": 5240055962,
+                    "causal": "Denunciado por tercero",
+                }
+            ],
+        }
+
     def test_cheque_response(self, sample_cheque_data: Dict[str, Any]) -> None:
         """Test ChequeResponse model."""
         data: Dict[str, Any] = {"status": 200, "results": sample_cheque_data}