Add test script for solar angle calculations (Issue pvlib#2448)

- Created test_solar_angles.py to verify solar angle calculations
- Tests zenith, azimuth, and elevation angles for different times of day
- Uses New York City as example location on spring equinox
- Verifies angles are within expected ranges and follow correct patterns

Author: OmarBahamida

test_solar_angles.py

@@ -0,0 +1,54 @@
+import pvlib
+import pandas as pd
+from datetime import datetime
+import pytz
+
+def test_solar_angles():
+    # Create a location (example: New York City)
+    latitude = 40.7128
+    longitude = -74.0060
+    tz = 'America/New_York'
+    location = pvlib.location.Location(latitude, longitude, tz=tz)
+    
+    # Create a time range for one day
+    start = pd.Timestamp('2024-03-20', tz=tz)  # Spring equinox
+    times = pd.date_range(start=start, periods=24, freq='H')
+    
+    # Calculate solar position
+    solpos = location.get_solarposition(times)
+    
+    # Print results for key times
+    print("\nSolar Angles for New York City on Spring Equinox:")
+    print("=" * 50)
+    
+    # Morning (9 AM)
+    morning = solpos.loc['2024-03-20 09:00:00-04:00']
+    print("\nMorning (9 AM):")
+    print(f"Solar Zenith: {morning['zenith']:.2f}°")
+    print(f"Solar Azimuth: {morning['azimuth']:.2f}°")
+    print(f"Solar Elevation: {morning['elevation']:.2f}°")
+    
+    # Solar Noon
+    noon = solpos.loc['2024-03-20 12:00:00-04:00']
+    print("\nSolar Noon:")
+    print(f"Solar Zenith: {noon['zenith']:.2f}°")
+    print(f"Solar Azimuth: {noon['azimuth']:.2f}°")
+    print(f"Solar Elevation: {noon['elevation']:.2f}°")
+    
+    # Evening (3 PM)
+    evening = solpos.loc['2024-03-20 15:00:00-04:00']
+    print("\nEvening (3 PM):")
+    print(f"Solar Zenith: {evening['zenith']:.2f}°")
+    print(f"Solar Azimuth: {evening['azimuth']:.2f}°")
+    print(f"Solar Elevation: {evening['elevation']:.2f}°")
+    
+    # Verify the angles make sense
+    print("\nVerification:")
+    print("- Zenith angle should be between 0° and 90°")
+    print("- Azimuth should be between 0° and 360°")
+    print("- Elevation should be between -90° and 90°")
+    print("- At solar noon, the sun should be at its highest point")
+    print("- The sun should rise in the east (azimuth ~90°) and set in the west (azimuth ~270°)")
+
+if __name__ == "__main__":
+    test_solar_angles()