feat: implement scenario comparison validation and API endpoint with comprehensive unit tests

2025-11-09 18:42:04 +01:00
parent c39dde3198
commit 02da881d3e
7 changed files with 483 additions and 5 deletions
--- a/services/scenario_validation.py
+++ b/services/scenario_validation.py
@@ -0,0 +1,106 @@
+from __future__ import annotations
+
+from dataclasses import dataclass
+from datetime import date
+from typing import Iterable, Sequence
+
+from models import Scenario, ScenarioStatus
+from services.exceptions import ScenarioValidationError
+
+ALLOWED_STATUSES: frozenset[ScenarioStatus] = frozenset(
+    {ScenarioStatus.DRAFT, ScenarioStatus.ACTIVE}
+)
+
+
+@dataclass(frozen=True)
+class _ValidationContext:
+    scenarios: Sequence[Scenario]
+
+    @property
+    def scenario_ids(self) -> list[int]:
+        return [scenario.id for scenario in self.scenarios if scenario.id is not None]
+
+
+class ScenarioComparisonValidator:
+    """Validates scenarios prior to comparison workflows."""
+
+    def validate(self, scenarios: Sequence[Scenario] | Iterable[Scenario]) -> None:
+        scenario_list = list(scenarios)
+        if len(scenario_list) < 2:
+            # Nothing to validate when fewer than two scenarios are provided.
+            return
+
+        context = _ValidationContext(scenario_list)
+
+        self._ensure_same_project(context)
+        self._ensure_allowed_status(context)
+        self._ensure_shared_currency(context)
+        self._ensure_timeline_overlap(context)
+        self._ensure_shared_primary_resource(context)
+
+    def _ensure_same_project(self, context: _ValidationContext) -> None:
+        project_ids = {scenario.project_id for scenario in context.scenarios}
+        if len(project_ids) > 1:
+            raise ScenarioValidationError(
+                code="SCENARIO_PROJECT_MISMATCH",
+                message="Selected scenarios do not belong to the same project.",
+                scenario_ids=context.scenario_ids,
+            )
+
+    def _ensure_allowed_status(self, context: _ValidationContext) -> None:
+        disallowed = [
+            scenario
+            for scenario in context.scenarios
+            if scenario.status not in ALLOWED_STATUSES
+        ]
+        if disallowed:
+            raise ScenarioValidationError(
+                code="SCENARIO_STATUS_INVALID",
+                message="Archived scenarios cannot be compared.",
+                scenario_ids=[
+                    scenario.id for scenario in disallowed if scenario.id is not None],
+            )
+
+    def _ensure_shared_currency(self, context: _ValidationContext) -> None:
+        currencies = {
+            scenario.currency
+            for scenario in context.scenarios
+            if scenario.currency is not None
+        }
+        if len(currencies) > 1:
+            raise ScenarioValidationError(
+                code="SCENARIO_CURRENCY_MISMATCH",
+                message="Scenarios use different currencies and cannot be compared.",
+                scenario_ids=context.scenario_ids,
+            )
+
+    def _ensure_timeline_overlap(self, context: _ValidationContext) -> None:
+        ranges = [
+            (scenario.start_date, scenario.end_date)
+            for scenario in context.scenarios
+            if scenario.start_date and scenario.end_date
+        ]
+        if len(ranges) < 2:
+            return
+
+        latest_start: date = max(start for start, _ in ranges)
+        earliest_end: date = min(end for _, end in ranges)
+        if latest_start > earliest_end:
+            raise ScenarioValidationError(
+                code="SCENARIO_TIMELINE_DISJOINT",
+                message="Scenario timelines do not overlap; adjust the comparison window.",
+                scenario_ids=context.scenario_ids,
+            )
+
+    def _ensure_shared_primary_resource(self, context: _ValidationContext) -> None:
+        resources = {
+            scenario.primary_resource
+            for scenario in context.scenarios
+            if scenario.primary_resource is not None
+        }
+        if len(resources) > 1:
+            raise ScenarioValidationError(
+                code="SCENARIO_RESOURCE_MISMATCH",
+                message="Scenarios target different primary resources and cannot be compared.",
+                scenario_ids=context.scenario_ids,
+            )