Add tests for sun angle calc

python/lsst/summit/utils/utils.py

@@ -1350,15 +1350,18 @@ def calcEclipticCoords(ra: float, dec: float) -> tuple[float, float]:
     return (np.rad2deg(lambda_), np.rad2deg(beta))
 
 
-def getSunAngle() -> float:
-    """Get the angle of the sun to the horizon. Positive numbers means the
-    sun is above the horizon, negative means it is below.
+def getSunAngle(time: Time | None = None) -> float:
+    """Get the angle of the sun to the horizon at the specified time.
+
+    If no time is specified, the current time is used. Positive numbers means
+    the sun is above the horizon, negative means it is below.
 
     Returns
     -------
     sun_alt : `float`
         The angle of the sun to the horizon, in degrees.
     """
-    now = Time.now()
-    sun_altaz = get_sun(now).transform_to(AltAz(obstime=now, location=SIMONYI_LOCATION))
+    if time is None:
+        time = Time.now()
+    sun_altaz = get_sun(time).transform_to(AltAz(obstime=time, location=SIMONYI_LOCATION))
     return sun_altaz.alt.deg

tests/test_utils.py

@@ -32,6 +32,7 @@
 import numpy as np
 from astro_metadata_translator import makeObservationInfo
 from astropy.coordinates import HeliocentricEclipticIAU76, SkyCoord
+from astropy.time import Time
 
 import lsst.afw.detection as afwDetect
 import lsst.afw.geom as afwGeom
@@ -56,6 +57,7 @@
     getExpPositionOffset,
     getFieldNameAndTileNumber,
     getQuantiles,
+    getSunAngle,
     quickSmooth,
 )
 
@@ -244,6 +246,19 @@ def test_getCurrentDayObs_humanStr(self):
         self.assertEqual(len(dateStr), 10)
         self.assertRegex(dateStr, r"\d{4}-\d{2}-\d{2}")
 
+    def test_getSunAngle(self):
+        """Just a basic sanity check on the range."""
+        testTime = Time("2021-09-15T16:00:00", format="isot", scale="utc")
+        sunAngle = getSunAngle(testTime)
+        self.assertIsInstance(sunAngle, float)
+        self.assertLess(sunAngle, 90.01)
+        self.assertGreater(sunAngle, -90.01)
+
+        sunAngle = getSunAngle()
+        self.assertIsInstance(sunAngle, float)
+        self.assertLess(sunAngle, 90.01)
+        self.assertGreater(sunAngle, -90.01)
+
 
 class QuantileTestCase(lsst.utils.tests.TestCase):
     def setUp(self) -> None: