ISSUE #198

* Add tests for precedence constraints.

Author: Sergio García Prado

packages/core/minos-microservice-saga/minos/saga/__init__.py

@@ -42,6 +42,7 @@
     MultipleOnExecuteException,
     MultipleOnFailureException,
     MultipleOnSuccessException,
+    OrderPrecedenceException,
     SagaException,
     SagaExecutionAlreadyExecutedException,
     SagaExecutionException,

packages/core/minos-microservice-saga/minos/saga/definitions/saga.py

@@ -27,6 +27,7 @@
     AlreadyCommittedException,
     AlreadyOnSagaException,
     EmptySagaException,
+    OrderPrecedenceException,
     SagaNotCommittedException,
 )
 from .operations import (
@@ -206,7 +207,9 @@ def add_step(self, step: Optional[Union[SagaOperation, T]], step_cls: type[T] =
                 step.order = 1
 
         if self.steps and step.order <= self.steps[-1].order:
-            raise ValueError("TODO")
+            raise OrderPrecedenceException(
+                f"Unsatisfied precedence constraints. Previous: {self.steps[-1].order} Current: {step.order} "
+            )
 
         self.steps.append(step)
         return step

packages/core/minos-microservice-saga/minos/saga/exceptions.py

@@ -159,7 +159,11 @@ class SagaRollbackExecutionStepException(SagaStepExecutionException):
 
 
 class AlreadyCommittedException(SagaException):
-    """Exception to be raised when trying to modifying an already committed saga."""
+    """Exception to be raised when trying to modify an already committed saga."""
+
+
+class OrderPrecedenceException(SagaException):
+    """Exception to be raised when ordering precedence of steps is not satisfied."""
 
 
 class ExecutorException(SagaException):

packages/core/minos-microservice-saga/tests/test_saga/test_definitions/test_saga.py

@@ -11,6 +11,7 @@
     EmptySagaException,
     EmptySagaStepException,
     LocalSagaStep,
+    OrderPrecedenceException,
     RemoteSagaStep,
     Saga,
     SagaException,
@@ -143,6 +144,7 @@ def test_step(self):
         saga.remote_step = mock
         with warnings.catch_warnings():
             warnings.simplefilter("ignore", DeprecationWarning)
+            # noinspection PyDeprecation
             step = saga.step()
 
         self.assertEqual(1, mock.call_count)
@@ -204,14 +206,30 @@ def test_build_execution(self):
 
     def test_add_step(self):
         step = RemoteSagaStep(send_create_order)
-        saga = Saga().remote_step(step).commit()
+        saga = Saga().add_step(step).commit()
 
         self.assertEqual([step], saga.steps)
 
-    def test_add_step_raises(self):
+    def test_add_step_raises_duplicated(self):
         step = RemoteSagaStep(send_create_order, saga=Saga())
         with self.assertRaises(AlreadyOnSagaException):
-            Saga().remote_step(step)
+            Saga().add_step(step)
+
+    def test_add_step_raises_precedence_lower(self):
+        step1 = RemoteSagaStep(send_create_order, order=2)
+        step2 = RemoteSagaStep(send_create_order, order=1)
+        saga = Saga()
+        saga.add_step(step1)
+        with self.assertRaises(OrderPrecedenceException):
+            saga.add_step(step2)
+
+    def test_add_step_raises_precedence_equal(self):
+        step1 = RemoteSagaStep(send_create_order, order=1)
+        step2 = RemoteSagaStep(send_create_order, order=1)
+        saga = Saga()
+        saga.add_step(step1)
+        with self.assertRaises(OrderPrecedenceException):
+            saga.add_step(step2)
 
     def test_raw(self):
         saga = ADD_ORDER