Handle invalid observer latitude in solar irradiation calculation

- Added a new exception `InvalidObserverLatitudeError` to handle cases where the observer's latitude is not within the valid range of -88 to 88 degrees.
- Modified the `calculate_direct_irradiation` method in `IrradiationCalculator` to return 90 or -90 based on `observer_latitude` when `irradiance_components` is empty.
- Updated the `_ensure_latitude_provided` method in `Observer` to raise `InvalidObserverLatitudeError` when the observer's latitude is not within the valid range.
- Added a new test `test_calculate_sunrise_sunset_invalid_latitude` to check if `InvalidObserverLatitudeError` is raised when the observer's latitude is not within the valid range.

src/pysolorie/exceptions.py

@@ -81,3 +81,34 @@ def __str__(self) -> str:
         :rtype: str
         """
         return f"{self.message}"
+
+
+class InvalidObserverLatitudeError(ValueError):
+    """
+    Exception raised when the observer's latitude is not within the valid range.
+
+    :param message: explanation of the error, defaults to
+                    "Invalid data: Observer latitude.
+                    Please ensure to provide a latitude between -88 and 88 degrees."
+    :type message: str, optional
+    """
+
+    def __init__(
+        self,
+        message: str = (
+            "Invalid data: Observer latitude. "
+            "Please ensure to provide a latitude between -88 and 88 degrees."
+        ),
+    ):
+        self.message = message
+        super().__init__(self.message)
+
+    def __str__(self) -> str:
+        """
+        String representation of the exception.
+
+        :return: formatted string indicating the invalid
+                 latitude and the error message
+        :rtype: str
+        """
+        return f"{self.message}"

src/pysolorie/numerical_integration.py

@@ -186,4 +186,13 @@ def neg_irradiation(beta: float):
             neg_irradiation, bounds=(-math.pi / 2, math.pi / 2), method="bounded"
         )
         optimal_beta = result.x
+
+        # Check if irradiance_components is empty
+        if not self.calculate_direct_irradiation(
+            math.degrees(optimal_beta), day_of_year
+        ):
+            observer_latitude = self._observer._ensure_latitude_provided()
+            # Return 90 or -90 based on observer_latitude
+            return 90 if observer_latitude >= 0 else -90
+
         return math.degrees(optimal_beta)

src/pysolorie/observer.py

@@ -15,7 +15,7 @@
 import math
 from typing import Optional
 
-from .exceptions import MissingObserverLatitudeError
+from .exceptions import InvalidObserverLatitudeError, MissingObserverLatitudeError
 from .sun_position import SunPosition
 
 
@@ -117,6 +117,8 @@ def calculate_sunrise_sunset(self, day_of_year: int) -> tuple:
     def _ensure_latitude_provided(self) -> float:
         if self.observer_latitude is None:
             raise MissingObserverLatitudeError()
+        if not math.radians(-88) <= self.observer_latitude <= math.radians(88):
+            raise InvalidObserverLatitudeError()
         return self.observer_latitude
 
     _observer_latitude: Optional[float]

tests/test_observer.py

@@ -54,7 +54,6 @@
             13 * 60 * 60,
             1.547,
         ),  # Test at Fairbanks on the 1st day of the year at 1pm
-        (90, 0, 1, 13 * 60 * 60, 1.972),  # Test at North Pole on January 1st at 1pm
     ],
 )
 def test_calculate_zenith_angle(
@@ -114,3 +113,14 @@ def test_calculate_sunrise_sunset(
     )
     assert sunrise_hour_angle == pytest.approx(expected_sunrise_hour_angle, abs=1e-3)
     assert sunset_hour_angle == pytest.approx(expected_sunset_hour_angle, abs=1e-3)
+
+
+def test_calculate_sunrise_sunset_invalid_latitude():
+    invalid_latitudes = [89, -89]
+    for invalid_latitude in invalid_latitudes:
+        observer = Observer(invalid_latitude)
+        with pytest.raises(
+            ValueError,
+            match="Invalid data: Observer latitude. ",
+        ):
+            observer.calculate_sunrise_sunset(day_of_year=172)