fix: delta profile when 2 result sets have different periods

due to opposite check of what it was supposed to, ie. check that
we only include periods that are given in the common period vector,
but instead there was a check that the separate result had a
period that was not in the common period vector.

Resolves equinor/ecalc-internal#298

src/libecalc/common/time_utils.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 import enum
+from collections.abc import Iterator
 from dataclasses import dataclass
 from datetime import date, datetime, timedelta
 from typing import Any, Optional, Self, Union
@@ -160,7 +161,7 @@ def create_periods(times: list[datetime], include_before: bool = True, include_a
 
         return Periods(periods=periods)
 
-    def __iter__(self):
+    def __iter__(self) -> Iterator[Period]:
         return self.periods.__iter__()
 
     def get_period(self, period: Period) -> Optional[Period]:

src/libecalc/presentation/simple_result/simple.py

@@ -132,7 +132,7 @@ def fit_to_periods(
             delta profile comparisons easier/possible.
 
         Args:
-            component (SimpleComponentResult): The component that should be fitted.
+            component (SimpleComponentResult): The component that should be fitted (should intersect all periods in the periods list).
             periods (Periods): The target periods. The provided periods should all exist in the component.
 
         Returns:
@@ -145,7 +145,7 @@ def fit_to_periods(
             emission.name: SimpleEmissionResult(name=emission.name, rate=[])
             for emission in component.emissions.values()
         }
-        for period_index, _period in enumerate(component.periods):
+        for period_index, _period in enumerate(periods):
             period = Period.intersection(_period, periods.period)
             if period:
                 start = periods.start_dates.index(period.start)
@@ -159,7 +159,8 @@ def fit_to_periods(
                         # Assume index exist if emission exist
                         emission.rate.append(component.emissions[emission.name].rate[period_index])
             else:
-                # This is a developer error, we should provide the correct period.
+                # It is a developer error if the component does not contain a period it should have according
+                # to the periods provided.
                 raise ProgrammingError(
                     f"Provided periods includes period not found in component {component.id}. "
                     f"Extraneous period: {period}. This should not happen, contact support."
@@ -256,7 +257,7 @@ def fit_to_periods(
         cls,
         model: "SimpleResultData",
         periods: Periods,
-    ):
+    ) -> "SimpleResultData":
         """
         Fit result to periods. Only a subset or the same set of periods is supported.
         Args:
@@ -323,7 +324,7 @@ def normalize_components(
         reference_model: "SimpleResultData",
         changed_model: "SimpleResultData",
         exclude: Optional[list[ComponentType]] = None,
-    ):
+    ) -> tuple["SimpleResultData", "SimpleResultData"]:
         if exclude is None:
             exclude = []
 
@@ -379,12 +380,14 @@ def delta_profile(
         first_date = max(changed_model.periods.first_date, reference_model.periods.first_date)
         last_date = min(changed_model.periods.last_date, reference_model.periods.last_date)
 
+        # intersection of the dates in both models
         all_dates_in_models = sorted(
             {date for date in reference_model.periods.all_dates if first_date <= date <= last_date}.union(
                 {date for date in changed_model.periods.all_dates if first_date <= date <= last_date}
             )
         )
-        # define new periods using all dates in both models
+
+        # define new periods using all dates in both models, skip extra periods before and after
         periods = Periods.create_periods(
             times=all_dates_in_models,
             include_after=False,